diff --git a/core/src/lib.rs b/core/src/lib.rs
index af9c71fe..5e406554 100644
--- a/core/src/lib.rs
+++ b/core/src/lib.rs
@@ -60,9 +60,14 @@ pub use cache::{
 
 /// Core types defining a Mentat knowledge base.
 mod types;
+mod tx_report;
 mod value_type_set;
 mod sql_types;
 
+pub use tx_report::{
+    TxReport,
+};
+
 pub use types::{
     Binding,
     Entid,
@@ -365,7 +370,6 @@ impl HasSchema for Schema {
     }
 }
 
-pub mod intern_set;
 pub mod counter;
 pub mod util;
 
diff --git a/core/src/tx_report.rs b/core/src/tx_report.rs
new file mode 100644
index 00000000..1b30278f
--- /dev/null
+++ b/core/src/tx_report.rs
@@ -0,0 +1,38 @@
+// Copyright 2018 Mozilla
+//
+// Licensed under the Apache License, Version 2.0 (the "License"); you may not use
+// this file except in compliance with the License. You may obtain a copy of the
+// License at http://www.apache.org/licenses/LICENSE-2.0
+// Unless required by applicable law or agreed to in writing, software distributed
+// under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
+// CONDITIONS OF ANY KIND, either express or implied. See the License for the
+// specific language governing permissions and limitations under the License.
+
+#![allow(dead_code)]
+
+use std::collections::{
+    BTreeMap,
+};
+
+use ::{
+    DateTime,
+    Entid,
+    Utc,
+};
+
+/// A transaction report summarizes an applied transaction.
+#[derive(Clone, Debug, Eq, Hash, Ord, PartialOrd, PartialEq)]
+pub struct TxReport {
+    /// The transaction ID of the transaction.
+    pub tx_id: Entid,
+
+    /// The timestamp when the transaction began to be committed.
+    pub tx_instant: DateTime<Utc>,
+
+    /// A map from string literal tempid to resolved or allocated entid.
+    ///
+    /// Every string literal tempid presented to the transactor either resolves via upsert to an
+    /// existing entid, or is allocated a new entid.  (It is possible for multiple distinct string
+    /// literal tempids to all unify to a single freshly allocated entid.)
+    pub tempids: BTreeMap<String, Entid>,
+}
diff --git a/core/src/types.rs b/core/src/types.rs
index 716f943f..992ddb38 100644
--- a/core/src/types.rs
+++ b/core/src/types.rs
@@ -47,6 +47,14 @@ use ::edn::{
     ValueRc,
 };
 
+use ::edn::entities::{
+    AttributePlace,
+    EntidOrIdent,
+    EntityPlace,
+    ValuePlace,
+    TransactableValueMarker,
+};
+
 use values;
 
 /// Represents one entid in the entid space.
@@ -73,6 +81,24 @@ impl From<KnownEntid> for TypedValue {
     }
 }
 
+impl<V: TransactableValueMarker> Into<EntityPlace<V>> for KnownEntid {
+    fn into(self) -> EntityPlace<V> {
+        EntityPlace::Entid(EntidOrIdent::Entid(self.0))
+    }
+}
+
+impl Into<AttributePlace> for KnownEntid {
+    fn into(self) -> AttributePlace {
+        AttributePlace::Entid(EntidOrIdent::Entid(self.0))
+    }
+}
+
+impl<V: TransactableValueMarker> Into<ValuePlace<V>> for KnownEntid {
+    fn into(self) -> ValuePlace<V> {
+        ValuePlace::Entid(EntidOrIdent::Entid(self.0))
+    }
+}
+
 /// The attribute of each Mentat assertion has a :db/valueType constraining the value to a
 /// particular set.  Mentat recognizes the following :db/valueType values.
 #[derive(Clone, Copy, Debug, Eq, Hash, Ord, PartialOrd, PartialEq)]
@@ -215,6 +241,9 @@ pub enum TypedValue {
     Uuid(Uuid),                        // It's only 128 bits, so this should be acceptable to clone.
 }
 
+/// `TypedValue` is the value type for programmatic use in transaction builders.
+impl TransactableValueMarker for TypedValue {}
+
 /// The values bound in a query specification can be:
 ///
 /// * Vecs of structured values, for multi-valued component attributes or nested expressions.
diff --git a/db/src/db.rs b/db/src/db.rs
index 327ef4ce..8ad0cc60 100644
--- a/db/src/db.rs
+++ b/db/src/db.rs
@@ -1119,20 +1119,22 @@ mod tests {
     use debug;
     use errors;
     use edn;
-    use mentat_core::{
-        HasSchema,
-        Keyword,
-        KnownEntid,
-        attribute,
-    };
-    use mentat_core::intern_set::{
+    use edn::{
         InternSet,
     };
-    use mentat_core::util::Either::*;
     use edn::entities::{
         OpType,
         TempId,
     };
+
+    use mentat_core::{
+        HasSchema,
+        Keyword,
+        KnownEntid,
+        TxReport,
+        attribute,
+    };
+    use mentat_core::util::Either::*;
     use rusqlite;
     use std::collections::{
         BTreeMap,
@@ -1141,7 +1143,6 @@ mod tests {
         Term,
         TermWithTempIds,
     };
-    use types::TxReport;
     use tx::{
         transact_terms,
     };
diff --git a/db/src/internal_types.rs b/db/src/internal_types.rs
index 72dda98d..782ff22d 100644
--- a/db/src/internal_types.rs
+++ b/db/src/internal_types.rs
@@ -17,7 +17,6 @@ use std::collections::{
     BTreeSet,
     HashMap,
 };
-use std::rc::Rc;
 
 use mentat_core::KnownEntid;
 
@@ -27,6 +26,14 @@ use edn;
 use edn::{
     SpannedValue,
     ValueAndSpan,
+    ValueRc,
+};
+use edn::entities;
+use edn::entities::{
+    EntityPlace,
+    OpType,
+    TempId,
+    TxFunction,
 };
 
 use errors;
@@ -47,13 +54,6 @@ use types::{
     TypedValue,
     ValueType,
 };
-use edn::entities;
-use edn::entities::{
-    EntityPlace,
-    OpType,
-    TempId,
-    TxFunction,
-};
 
 impl TransactableValue for ValueAndSpan {
     fn into_typed_value(self, schema: &Schema, value_type: ValueType) -> Result<TypedValue> {
@@ -72,7 +72,7 @@ impl TransactableValue for ValueAndSpan {
                     bail!(DbErrorKind::InputError(errors::InputError::BadEntityPlace))
                 }
             },
-            Text(v) => Ok(EntityPlace::TempId(TempId::External(v))),
+            Text(v) => Ok(EntityPlace::TempId(TempId::External(v).into())),
             List(ls) => {
                 let mut it = ls.iter();
                 match (it.next().map(|x| &x.inner), it.next(), it.next(), it.next()) {
@@ -107,7 +107,7 @@ impl TransactableValue for ValueAndSpan {
     }
 
     fn as_tempid(&self) -> Option<TempId> {
-        self.inner.as_text().cloned().map(TempId::External)
+        self.inner.as_text().cloned().map(TempId::External).map(|v| v.into())
     }
 }
 
@@ -123,7 +123,7 @@ impl TransactableValue for TypedValue {
         match self {
             TypedValue::Ref(x) => Ok(EntityPlace::Entid(entities::EntidOrIdent::Entid(x))),
             TypedValue::Keyword(x) => Ok(EntityPlace::Entid(entities::EntidOrIdent::Ident((*x).clone()))),
-            TypedValue::String(x) => Ok(EntityPlace::TempId(TempId::External((*x).clone()))),
+            TypedValue::String(x) => Ok(EntityPlace::TempId(TempId::External((*x).clone()).into())),
             TypedValue::Boolean(_) |
             TypedValue::Long(_) |
             TypedValue::Double(_) |
@@ -134,7 +134,7 @@ impl TransactableValue for TypedValue {
 
     fn as_tempid(&self) -> Option<TempId> {
         match self {
-            &TypedValue::String(ref s) => Some(TempId::External((**s).clone())),
+            &TypedValue::String(ref s) => Some(TempId::External((**s).clone()).into()),
             _ => None,
         }
     }
@@ -150,10 +150,10 @@ use self::Either::*;
 pub type KnownEntidOr<T> = Either<KnownEntid, T>;
 pub type TypedValueOr<T> = Either<TypedValue, T>;
 
-pub type TempIdHandle = Rc<TempId>;
+pub type TempIdHandle = ValueRc<TempId>;
 pub type TempIdMap = HashMap<TempIdHandle, KnownEntid>;
 
-pub type LookupRef = Rc<AVPair>;
+pub type LookupRef = ValueRc<AVPair>;
 
 /// Internal representation of an entid on its way to resolution.  We either have the simple case (a
 /// numeric entid), a lookup-ref that still needs to be resolved (an atomized [a v] pair), or a temp
diff --git a/db/src/lib.rs b/db/src/lib.rs
index c7cf40eb..bd8fe154 100644
--- a/db/src/lib.rs
+++ b/db/src/lib.rs
@@ -106,7 +106,6 @@ pub use types::{
     DB,
     PartitionMap,
     TransactableValue,
-    TxReport,
 };
 
 pub fn to_namespaced_keyword(s: &str) -> Result<symbols::Keyword> {
diff --git a/db/src/tx.rs b/db/src/tx.rs
index dc777c34..4179fa24 100644
--- a/db/src/tx.rs
+++ b/db/src/tx.rs
@@ -56,9 +56,6 @@ use std::collections::{
 use std::iter::{
     once,
 };
-use std::rc::{
-    Rc,
-};
 
 use db;
 use db::{
@@ -66,6 +63,7 @@ use db::{
     PartitionMapping,
 };
 use edn::{
+    InternSet,
     Keyword,
 };
 use entids;
@@ -96,13 +94,12 @@ use mentat_core::{
     DateTime,
     KnownEntid,
     Schema,
+    TxReport,
     Utc,
     attribute,
     now,
 };
 
-use mentat_core::intern_set::InternSet;
-
 use edn::entities as entmod;
 use edn::entities::{
     AttributePlace,
@@ -123,7 +120,6 @@ use types::{
     Entid,
     PartitionMap,
     TransactableValue,
-    TxReport,
     TypedValue,
     ValueType,
 };
@@ -304,15 +300,11 @@ impl<'conn, 'a, W> Tx<'conn, 'a, W> where W: TransactWatcher {
                 Ok(self.lookup_refs.intern((lr_a, lr_typed_value)))
             }
 
-            fn intern_temp_id(&mut self, temp_id: TempId) -> Rc<TempId> {
-                self.temp_ids.intern(temp_id)
-            }
-
             /// Allocate private internal tempids reserved for Mentat.  Internal tempids just need to be
             /// unique within one transaction; they should never escape a transaction.
             fn allocate_mentat_id<W: TransactableValue>(&mut self) -> entmod::EntityPlace<W> {
                 self.mentat_id_count += 1;
-                entmod::EntityPlace::TempId(TempId::Internal(self.mentat_id_count))
+                entmod::EntityPlace::TempId(TempId::Internal(self.mentat_id_count).into())
             }
 
             fn entity_e_into_term_e<W: TransactableValue>(&mut self, x: entmod::EntityPlace<W>) -> Result<KnownEntidOr<LookupRefOrTempId>> {
@@ -326,7 +318,7 @@ impl<'conn, 'a, W> Tx<'conn, 'a, W> where W: TransactWatcher {
                     },
 
                     entmod::EntityPlace::TempId(e) => {
-                        Ok(Either::Right(LookupRefOrTempId::TempId(self.intern_temp_id(e))))
+                        Ok(Either::Right(LookupRefOrTempId::TempId(self.temp_ids.intern(e))))
                     },
 
                     entmod::EntityPlace::LookupRef(ref lookup_ref) => {
@@ -372,7 +364,7 @@ impl<'conn, 'a, W> Tx<'conn, 'a, W> where W: TransactWatcher {
                                 // that the given value is in the attribute's value set, or (in
                                 // limited cases) coerce the value into the attribute's value set.
                                 match v.as_tempid() {
-                                    Some(tempid) => Ok(Either::Right(LookupRefOrTempId::TempId(self.intern_temp_id(tempid)))),
+                                    Some(tempid) => Ok(Either::Right(LookupRefOrTempId::TempId(self.temp_ids.intern(tempid)))),
                                     None => {
                                         if let TypedValue::Ref(entid) = v.into_typed_value(&self.schema, ValueType::Ref)? {
                                             Ok(Either::Left(KnownEntid(entid)))
@@ -388,7 +380,7 @@ impl<'conn, 'a, W> Tx<'conn, 'a, W> where W: TransactWatcher {
                                 Ok(Either::Left(KnownEntid(self.entity_a_into_term_a(entid)?))),
 
                             entmod::ValuePlace::TempId(tempid) =>
-                                Ok(Either::Right(LookupRefOrTempId::TempId(self.intern_temp_id(tempid)))),
+                                Ok(Either::Right(LookupRefOrTempId::TempId(self.temp_ids.intern(tempid)))),
 
                             entmod::ValuePlace::LookupRef(ref lookup_ref) =>
                                 Ok(Either::Right(LookupRefOrTempId::LookupRef(self.intern_lookup_ref(lookup_ref)?))),
@@ -459,7 +451,7 @@ impl<'conn, 'a, W> Tx<'conn, 'a, W> where W: TransactWatcher {
                                 // limited cases) coerce the value into the attribute's value set.
                                 if attribute.value_type == ValueType::Ref {
                                     match v.as_tempid() {
-                                        Some(tempid) => Either::Right(LookupRefOrTempId::TempId(in_process.intern_temp_id(tempid))),
+                                        Some(tempid) => Either::Right(LookupRefOrTempId::TempId(in_process.temp_ids.intern(tempid))),
                                         None => v.into_typed_value(&self.schema, attribute.value_type).map(Either::Left)?,
                                     }
                                 } else {
@@ -471,7 +463,7 @@ impl<'conn, 'a, W> Tx<'conn, 'a, W> where W: TransactWatcher {
                                 Either::Left(TypedValue::Ref(in_process.entity_a_into_term_a(entid)?)),
 
                             entmod::ValuePlace::TempId(tempid) =>
-                                Either::Right(LookupRefOrTempId::TempId(in_process.intern_temp_id(tempid))),
+                                Either::Right(LookupRefOrTempId::TempId(in_process.temp_ids.intern(tempid))),
 
                             entmod::ValuePlace::LookupRef(ref lookup_ref) => {
                                 if attribute.value_type != ValueType::Ref {
@@ -622,7 +614,7 @@ impl<'conn, 'a, W> Tx<'conn, 'a, W> where W: TransactWatcher {
         let (terms_with_temp_ids_and_lookup_refs, tempid_set, lookup_ref_set) = self.entities_into_terms_with_temp_ids_and_lookup_refs(entities)?;
 
         // Pipeline stage 2: resolve lookup refs -> terms with tempids.
-        let lookup_ref_avs: Vec<&(i64, TypedValue)> = lookup_ref_set.inner.iter().map(|rc| &**rc).collect();
+        let lookup_ref_avs: Vec<&(i64, TypedValue)> = lookup_ref_set.iter().map(|rc| &**rc).collect();
         let lookup_ref_map: AVMap = self.store.resolve_avs(&lookup_ref_avs[..])?;
 
         let terms_with_temp_ids = self.resolve_lookup_refs(&lookup_ref_map, terms_with_temp_ids_and_lookup_refs)?;
@@ -703,8 +695,8 @@ impl<'conn, 'a, W> Tx<'conn, 'a, W> where W: TransactWatcher {
         }
 
         // Verify that every tempid we interned either resolved or has been allocated.
-        assert_eq!(tempids.len(), tempid_set.inner.len());
-        for tempid in &tempid_set.inner {
+        assert_eq!(tempids.len(), tempid_set.len());
+        for tempid in tempid_set.iter() {
             assert!(tempids.contains_key(&**tempid));
         }
 
diff --git a/db/src/types.rs b/db/src/types.rs
index 70ea4964..138dd66b 100644
--- a/db/src/types.rs
+++ b/db/src/types.rs
@@ -95,23 +95,6 @@ pub type AVMap<'a> = HashMap<&'a AVPair, Entid>;
 // represents a set of entids that are correspond to attributes
 pub type AttributeSet = BTreeSet<Entid>;
 
-/// A transaction report summarizes an applied transaction.
-#[derive(Clone, Debug, Eq, Hash, Ord, PartialOrd, PartialEq)]
-pub struct TxReport {
-    /// The transaction ID of the transaction.
-    pub tx_id: Entid,
-
-    /// The timestamp when the transaction began to be committed.
-    pub tx_instant: DateTime<Utc>,
-
-    /// A map from string literal tempid to resolved or allocated entid.
-    ///
-    /// Every string literal tempid presented to the transactor either resolves via upsert to an
-    /// existing entid, or is allocated a new entid.  (It is possible for multiple distinct string
-    /// literal tempids to all unify to a single freshly allocated entid.)
-    pub tempids: BTreeMap<String, Entid>,
-}
-
 /// The transactor is tied to `edn::ValueAndSpan` right now, but in the future we'd like to support
 /// `TypedValue` directly for programmatic use.  `TransactableValue` encapsulates the interface
 /// value types (i.e., values in the value place) need to support to be transacted.
diff --git a/edn/src/edn.rustpeg b/edn/src/edn.rustpeg
index 21926b1f..2a642bea 100644
--- a/edn/src/edn.rustpeg
+++ b/edn/src/edn.rustpeg
@@ -260,7 +260,7 @@ tx_function -> TxFunction
     = "(" __ n:$(symbol_name) __ ")" { TxFunction { op: PlainSymbol::plain(n) } }
 
 entity_place -> EntityPlace<ValueAndSpan>
-    = v:raw_text { EntityPlace::TempId(TempId::External(v)) }
+    = v:raw_text { EntityPlace::TempId(TempId::External(v).into()) }
     / v:entid { EntityPlace::Entid(v) }
     / v:lookup_ref { EntityPlace::LookupRef(v) }
     / v:tx_function { EntityPlace::TxFunction(v) }
diff --git a/edn/src/entities.rs b/edn/src/entities.rs
index 17610e20..c6c27704 100644
--- a/edn/src/entities.rs
+++ b/edn/src/entities.rs
@@ -13,11 +13,29 @@
 use std::collections::BTreeMap;
 use std::fmt;
 
+use value_rc::{
+    ValueRc,
+};
+
 use symbols::{
     Keyword,
     PlainSymbol,
 };
 
+use types::{
+    ValueAndSpan,
+};
+
+/// `EntityPlace` and `ValuePlace` embed values, either directly (i.e., `ValuePlace::Atom`) or
+/// indirectly (i.e., `EntityPlace::LookupRef`).  In order to maintain the graph of `Into` and
+/// `From` relations, we need to ensure that `{Value,Entity}Place` can't match as a potential value.
+/// (If it does, the `impl Into<T> for T` default conflicts.) This marker trait allows to mark
+/// acceptable values, thereby removing `{Entity,Value}Place` from consideration.
+pub trait TransactableValueMarker {}
+
+/// `ValueAndSpan` is the value type coming out of the entity parser.
+impl TransactableValueMarker for ValueAndSpan {}
+
 /// A tempid, either an external tempid given in a transaction (usually as an `Value::Text`),
 /// or an internal tempid allocated by Mentat itself.
 #[derive(Clone, Debug, Eq, Hash, Ord, PartialOrd, PartialEq)]
@@ -50,6 +68,18 @@ pub enum EntidOrIdent {
     Ident(Keyword),
 }
 
+impl From<i64> for EntidOrIdent {
+    fn from(v: i64) -> Self {
+        EntidOrIdent::Entid(v)
+    }
+}
+
+impl From<Keyword> for EntidOrIdent {
+    fn from(v: Keyword) -> Self {
+        EntidOrIdent::Ident(v)
+    }
+}
+
 impl EntidOrIdent {
     pub fn unreversed(&self) -> Option<EntidOrIdent> {
         match self {
@@ -93,7 +123,7 @@ pub enum ValuePlace<V> {
     Entid(EntidOrIdent),
     // We never know at parse-time whether a string is really a tempid, but we will often know when
     // building entities programmatically.
-    TempId(TempId),
+    TempId(ValueRc<TempId>),
     LookupRef(LookupRef<V>),
     TxFunction(TxFunction),
     Vector(Vec<ValuePlace<V>>),
@@ -101,19 +131,103 @@ pub enum ValuePlace<V> {
     MapNotation(MapNotation<V>),
 }
 
+impl<V: TransactableValueMarker> From<EntidOrIdent> for ValuePlace<V> {
+    fn from(v: EntidOrIdent) -> Self {
+        ValuePlace::Entid(v)
+    }
+}
+
+impl<V: TransactableValueMarker> From<TempId> for ValuePlace<V> {
+    fn from(v: TempId) -> Self {
+        ValuePlace::TempId(v.into())
+    }
+}
+
+impl<V: TransactableValueMarker> From<ValueRc<TempId>> for ValuePlace<V> {
+    fn from(v: ValueRc<TempId>) -> Self {
+        ValuePlace::TempId(v)
+    }
+}
+
+impl<V: TransactableValueMarker> From<LookupRef<V>> for ValuePlace<V> {
+    fn from(v: LookupRef<V>) -> Self {
+        ValuePlace::LookupRef(v)
+    }
+}
+
+impl<V: TransactableValueMarker> From<TxFunction> for ValuePlace<V> {
+    fn from(v: TxFunction) -> Self {
+        ValuePlace::TxFunction(v)
+    }
+}
+
+impl<V: TransactableValueMarker> From<Vec<ValuePlace<V>>> for ValuePlace<V> {
+    fn from(v: Vec<ValuePlace<V>>) -> Self {
+        ValuePlace::Vector(v)
+    }
+}
+
+impl<V: TransactableValueMarker> From<V> for ValuePlace<V> {
+    fn from(v: V) -> Self {
+        ValuePlace::Atom(v)
+    }
+}
+
+impl<V: TransactableValueMarker> From<MapNotation<V>> for ValuePlace<V> {
+    fn from(v: MapNotation<V>) -> Self {
+        ValuePlace::MapNotation(v)
+    }
+}
+
 #[derive(Clone, Debug, Eq, Hash, Ord, PartialOrd, PartialEq)]
 pub enum EntityPlace<V> {
     Entid(EntidOrIdent),
-    TempId(TempId),
+    TempId(ValueRc<TempId>),
     LookupRef(LookupRef<V>),
     TxFunction(TxFunction),
 }
 
+impl<V, E: Into<EntidOrIdent>> From<E> for EntityPlace<V> {
+    fn from(v: E) -> Self {
+        EntityPlace::Entid(v.into())
+    }
+}
+
+impl<V: TransactableValueMarker> From<TempId> for EntityPlace<V> {
+    fn from(v: TempId) -> Self {
+        EntityPlace::TempId(v.into())
+    }
+}
+
+impl<V: TransactableValueMarker> From<ValueRc<TempId>> for EntityPlace<V> {
+    fn from(v: ValueRc<TempId>) -> Self {
+        EntityPlace::TempId(v)
+    }
+}
+
+impl<V: TransactableValueMarker> From<LookupRef<V>> for EntityPlace<V> {
+    fn from(v: LookupRef<V>) -> Self {
+        EntityPlace::LookupRef(v)
+    }
+}
+
+impl<V: TransactableValueMarker> From<TxFunction> for EntityPlace<V> {
+    fn from(v: TxFunction) -> Self {
+        EntityPlace::TxFunction(v)
+    }
+}
+
 #[derive(Clone, Debug, Eq, Hash, Ord, PartialOrd, PartialEq)]
 pub enum AttributePlace {
     Entid(EntidOrIdent),
 }
 
+impl<A: Into<EntidOrIdent>> From<A> for AttributePlace {
+    fn from(v: A) -> Self {
+        AttributePlace::Entid(v.into())
+    }
+}
+
 #[derive(Clone, Copy, Debug, Eq, Hash, Ord, PartialOrd, PartialEq)]
 pub enum OpType {
     Add,
diff --git a/core/src/intern_set.rs b/edn/src/intern_set.rs
similarity index 75%
rename from core/src/intern_set.rs
rename to edn/src/intern_set.rs
index 524cebf9..65d4e704 100644
--- a/core/src/intern_set.rs
+++ b/edn/src/intern_set.rs
@@ -12,7 +12,14 @@
 
 use std::collections::HashSet;
 use std::hash::Hash;
-use std::rc::Rc;
+use std::ops::{
+    Deref,
+    DerefMut,
+};
+
+use ::{
+    ValueRc,
+};
 
 /// An `InternSet` allows to "intern" some potentially large values, maintaining a single value
 /// instance owned by the `InternSet` and leaving consumers with lightweight ref-counted handles to
@@ -23,7 +30,21 @@ use std::rc::Rc;
 /// See https://en.wikipedia.org/wiki/String_interning for discussion.
 #[derive(Clone, Debug, Default, Eq, PartialEq)]
 pub struct InternSet<T> where T: Eq + Hash {
-    pub inner: HashSet<Rc<T>>,
+    inner: HashSet<ValueRc<T>>,
+}
+
+impl<T> Deref for InternSet<T> where T: Eq + Hash {
+    type Target = HashSet<ValueRc<T>>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.inner
+    }
+}
+
+impl<T> DerefMut for InternSet<T> where T: Eq + Hash {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.inner
+    }
 }
 
 impl<T> InternSet<T> where T: Eq + Hash {
@@ -33,20 +54,15 @@ impl<T> InternSet<T> where T: Eq + Hash {
         }
     }
 
-    pub fn len(&self) -> usize {
-        self.inner.len()
-    }
-
     /// Intern a value, providing a ref-counted handle to the interned value.
     ///
     /// ```
-    /// use std::rc::Rc;
-    /// use mentat_core::intern_set::InternSet;
+    /// use edn::{InternSet, ValueRc};
     ///
     /// let mut s = InternSet::new();
     ///
     /// let one = "foo".to_string();
-    /// let two = Rc::new("foo".to_string());
+    /// let two = ValueRc::new("foo".to_string());
     ///
     /// let out_one = s.intern(one);
     /// assert_eq!(out_one, two);
@@ -54,11 +70,11 @@ impl<T> InternSet<T> where T: Eq + Hash {
     ///
     /// let out_two = s.intern(two);
     /// assert_eq!(out_one, out_two);
-    /// assert_eq!(1, s.inner.len());
+    /// assert_eq!(1, s.len());
     /// // assert!(&out_one.ptr_eq(&out_two));   // Nightly-only.
     /// ```
-    pub fn intern<R: Into<Rc<T>>>(&mut self, value: R) -> Rc<T> {
-        let key: Rc<T> = value.into();
+    pub fn intern<R: Into<ValueRc<T>>>(&mut self, value: R) -> ValueRc<T> {
+        let key: ValueRc<T> = value.into();
         if self.inner.insert(key.clone()) {
             key
         } else {
diff --git a/edn/src/lib.rs b/edn/src/lib.rs
index a2a1dbcc..f9c57c94 100644
--- a/edn/src/lib.rs
+++ b/edn/src/lib.rs
@@ -23,6 +23,10 @@ extern crate serde;
 extern crate serde_derive;
 
 pub mod entities;
+pub mod intern_set;
+pub use intern_set::{
+    InternSet,
+};
 // Intentionally not pub.
 mod namespaceable_name;
 pub mod query;
diff --git a/ffi/src/lib.rs b/ffi/src/lib.rs
index b08d7d38..98c45d8d 100644
--- a/ffi/src/lib.rs
+++ b/ffi/src/lib.rs
@@ -120,7 +120,6 @@ pub use mentat::entity_builder::{
     BuildTerms,
     EntityBuilder,
     InProgressBuilder,
-    IntoThing,
 };
 
 pub mod android;
@@ -339,7 +338,7 @@ pub unsafe extern "C" fn in_progress_entity_builder_from_temp_id<'m>(in_progress
 pub unsafe extern "C" fn in_progress_entity_builder_from_entid<'m>(in_progress: *mut InProgress<'m, 'm>, entid: c_longlong) -> *mut EntityBuilder<InProgressBuilder> {
     assert_not_null!(in_progress);
     let in_progress = Box::from_raw(in_progress);
-    Box::into_raw(Box::new(in_progress.builder().describe(&KnownEntid(entid))))
+    Box::into_raw(Box::new(in_progress.builder().describe(KnownEntid(entid))))
 }
 
 /// Starts a new transaction and creates a builder using the transaction
@@ -392,7 +391,7 @@ pub unsafe extern "C" fn store_entity_builder_from_entid<'a, 'c>(store: *mut Sto
     assert_not_null!(store);
     let store = &mut *store;
     let result = store.begin_transaction().and_then(|in_progress| {
-        Ok(in_progress.builder().describe(&KnownEntid(entid)))
+        Ok(in_progress.builder().describe(KnownEntid(entid)))
     });
     translate_result(result, error)
 }
@@ -418,7 +417,7 @@ pub unsafe extern "C" fn in_progress_builder_add_string<'a, 'c>(
     let builder = &mut *builder;
     let kw = kw_from_string(c_char_to_string(kw));
     let value: TypedValue = c_char_to_string(value).into();
-    translate_void_result(builder.add_kw(KnownEntid(entid), &kw, value), error);
+    translate_void_result(builder.add(KnownEntid(entid), kw, value), error);
 }
 
 /// Uses `builder` to assert `value` for `kw` on entity `entid`.
@@ -441,7 +440,7 @@ pub unsafe extern "C" fn in_progress_builder_add_long<'a, 'c>(
     let builder = &mut *builder;
     let kw = kw_from_string(c_char_to_string(kw));
     let value: TypedValue = TypedValue::Long(value);
-    translate_void_result(builder.add_kw(KnownEntid(entid), &kw, value), error);
+    translate_void_result(builder.add(KnownEntid(entid), kw, value), error);
 }
 
 /// Uses `builder` to assert `value` for `kw` on entity `entid`.
@@ -465,7 +464,7 @@ pub unsafe extern "C" fn in_progress_builder_add_ref<'a, 'c>(
     let builder = &mut *builder;
     let kw = kw_from_string(c_char_to_string(kw));
     let value: TypedValue = TypedValue::Ref(value);
-    translate_void_result(builder.add_kw(KnownEntid(entid), &kw, value), error);
+    translate_void_result(builder.add(KnownEntid(entid), kw, value), error);
 }
 
 /// Uses `builder` to assert `value` for `kw` on entity `entid`.
@@ -490,7 +489,7 @@ pub unsafe extern "C" fn in_progress_builder_add_keyword<'a, 'c>(
     let builder = &mut *builder;
     let kw = kw_from_string(c_char_to_string(kw));
     let value: TypedValue = kw_from_string(c_char_to_string(value)).into();
-    translate_void_result(builder.add_kw(KnownEntid(entid), &kw, value), error);
+    translate_void_result(builder.add(KnownEntid(entid), kw, value), error);
 }
 
 /// Uses `builder` to assert `value` for `kw` on entity `entid`.
@@ -514,7 +513,7 @@ pub unsafe extern "C" fn in_progress_builder_add_boolean<'a, 'c>(
     let builder = &mut *builder;
     let kw = kw_from_string(c_char_to_string(kw));
     let value: TypedValue = value.into();
-    translate_void_result(builder.add_kw(KnownEntid(entid), &kw, value), error);
+    translate_void_result(builder.add(KnownEntid(entid), kw, value), error);
 }
 
 /// Uses `builder` to assert `value` for `kw` on entity `entid`.
@@ -538,7 +537,7 @@ pub unsafe extern "C" fn in_progress_builder_add_double<'a, 'c>(
     let builder = &mut *builder;
     let kw = kw_from_string(c_char_to_string(kw));
     let value: TypedValue = value.into();
-    translate_void_result(builder.add_kw(KnownEntid(entid), &kw, value), error);
+    translate_void_result(builder.add(KnownEntid(entid), kw, value), error);
 }
 
 /// Uses `builder` to assert `value` for `kw` on entity `entid`.
@@ -562,7 +561,7 @@ pub unsafe extern "C" fn in_progress_builder_add_timestamp<'a, 'c>(
     let builder = &mut *builder;
     let kw = kw_from_string(c_char_to_string(kw));
     let value: TypedValue = TypedValue::instant(value);
-    translate_void_result(builder.add_kw(KnownEntid(entid), &kw, value), error);
+    translate_void_result(builder.add(KnownEntid(entid), kw, value), error);
 }
 
 /// Uses `builder` to assert `value` for `kw` on entity `entid`.
@@ -588,7 +587,7 @@ pub unsafe extern "C" fn in_progress_builder_add_uuid<'a, 'c>(
     let value = &*value;
     let value = Uuid::from_bytes(value).expect("valid uuid");
     let value: TypedValue = value.into();
-    translate_void_result(builder.add_kw(KnownEntid(entid), &kw, value), error);
+    translate_void_result(builder.add(KnownEntid(entid), kw, value), error);
 }
 
 /// Uses `builder` to retract `value` for `kw` on entity `entid`.
@@ -612,7 +611,7 @@ pub unsafe extern "C" fn in_progress_builder_retract_string<'a, 'c>(
     let builder = &mut *builder;
     let kw = kw_from_string(c_char_to_string(kw));
     let value: TypedValue = c_char_to_string(value).into();
-    translate_void_result(builder.retract_kw(KnownEntid(entid), &kw, value), error);
+    translate_void_result(builder.retract(KnownEntid(entid), kw, value), error);
 }
 
 /// Uses `builder` to retract `value` for `kw` on entity `entid`.
@@ -636,7 +635,7 @@ pub unsafe extern "C" fn in_progress_builder_retract_long<'a, 'c>(
     let builder = &mut *builder;
     let kw = kw_from_string(c_char_to_string(kw));
     let value: TypedValue = TypedValue::Long(value);
-    translate_void_result(builder.retract_kw(KnownEntid(entid), &kw, value), error);
+    translate_void_result(builder.retract(KnownEntid(entid), kw, value), error);
 }
 
 /// Uses `builder` to retract `value` for `kw` on entity `entid`.
@@ -660,7 +659,7 @@ pub unsafe extern "C" fn in_progress_builder_retract_ref<'a, 'c>(
     let builder = &mut *builder;
     let kw = kw_from_string(c_char_to_string(kw));
     let value: TypedValue = TypedValue::Ref(value);
-    translate_void_result(builder.retract_kw(KnownEntid(entid), &kw, value), error);
+    translate_void_result(builder.retract(KnownEntid(entid), kw, value), error);
 }
 
 
@@ -685,7 +684,7 @@ pub unsafe extern "C" fn in_progress_builder_retract_keyword<'a, 'c>(
     let builder = &mut *builder;
     let kw = kw_from_string(c_char_to_string(kw));
     let value: TypedValue = kw_from_string(c_char_to_string(value)).into();
-    translate_void_result(builder.retract_kw(KnownEntid(entid), &kw, value), error);
+    translate_void_result(builder.retract(KnownEntid(entid), kw, value), error);
 }
 
 /// Uses `builder` to retract `value` for `kw` on entity `entid`.
@@ -709,7 +708,7 @@ pub unsafe extern "C" fn in_progress_builder_retract_boolean<'a, 'c>(
     let builder = &mut *builder;
     let kw = kw_from_string(c_char_to_string(kw));
     let value: TypedValue = value.into();
-    translate_void_result(builder.retract_kw(KnownEntid(entid), &kw, value), error);
+    translate_void_result(builder.retract(KnownEntid(entid), kw, value), error);
 }
 
 /// Uses `builder` to retract `value` for `kw` on entity `entid`.
@@ -733,7 +732,7 @@ pub unsafe extern "C" fn in_progress_builder_retract_double<'a, 'c>(
     let builder = &mut *builder;
     let kw = kw_from_string(c_char_to_string(kw));
     let value: TypedValue = value.into();
-    translate_void_result(builder.retract_kw(KnownEntid(entid), &kw, value), error);
+    translate_void_result(builder.retract(KnownEntid(entid), kw, value), error);
 }
 
 /// Uses `builder` to retract `value` for `kw` on entity `entid`.
@@ -757,7 +756,7 @@ pub unsafe extern "C" fn in_progress_builder_retract_timestamp<'a, 'c>(
     let builder = &mut *builder;
     let kw = kw_from_string(c_char_to_string(kw));
     let value: TypedValue = TypedValue::instant(value);
-    translate_void_result(builder.retract_kw(KnownEntid(entid), &kw, value), error);
+    translate_void_result(builder.retract(KnownEntid(entid), kw, value), error);
 }
 
 /// Uses `builder` to retract `value` for `kw` on entity `entid`.
@@ -785,7 +784,7 @@ pub unsafe extern "C" fn in_progress_builder_retract_uuid<'a, 'c>(
     let value = &*value;
     let value = Uuid::from_bytes(value).expect("valid uuid");
     let value: TypedValue = value.into();
-    translate_void_result(builder.retract_kw(KnownEntid(entid), &kw, value), error);
+    translate_void_result(builder.retract(KnownEntid(entid), kw, value), error);
 }
 
 /// Transacts and commits all the assertions and retractions that have been performed
@@ -842,7 +841,7 @@ pub unsafe extern "C" fn entity_builder_add_string<'a, 'c>(
     let builder = &mut *builder;
     let kw = kw_from_string(c_char_to_string(kw));
     let value: TypedValue = c_char_to_string(value).into();
-    translate_void_result(builder.add_kw(&kw, value), error);
+    translate_void_result(builder.add(kw, value), error);
 }
 
 /// Uses `builder` to assert `value` for `kw` on entity `entid`.
@@ -865,7 +864,7 @@ pub unsafe extern "C" fn entity_builder_add_long<'a, 'c>(
     let builder = &mut *builder;
     let kw = kw_from_string(c_char_to_string(kw));
     let value: TypedValue = TypedValue::Long(value);
-    translate_void_result(builder.add_kw(&kw, value), error);
+    translate_void_result(builder.add(kw, value), error);
 }
 
 /// Uses `builder` to assert `value` for `kw` on entity `entid`.
@@ -888,7 +887,7 @@ pub unsafe extern "C" fn entity_builder_add_ref<'a, 'c>(
     let builder = &mut *builder;
     let kw = kw_from_string(c_char_to_string(kw));
     let value: TypedValue = TypedValue::Ref(value);
-    translate_void_result(builder.add_kw(&kw, value), error);
+    translate_void_result(builder.add(kw, value), error);
 }
 
 /// Uses `builder` to assert `value` for `kw` on entity `entid`.
@@ -911,7 +910,7 @@ pub unsafe extern "C" fn entity_builder_add_keyword<'a, 'c>(
     let builder = &mut *builder;
     let kw = kw_from_string(c_char_to_string(kw));
     let value: TypedValue = kw_from_string(c_char_to_string(value)).into();
-    translate_void_result(builder.add_kw(&kw, value), error);
+    translate_void_result(builder.add(kw, value), error);
 }
 
 /// Uses `builder` to assert `value` for `kw` on entity `entid`.
@@ -934,7 +933,7 @@ pub unsafe extern "C" fn entity_builder_add_boolean<'a, 'c>(
     let builder = &mut *builder;
     let kw = kw_from_string(c_char_to_string(kw));
     let value: TypedValue = value.into();
-    translate_void_result(builder.add_kw(&kw, value), error);
+    translate_void_result(builder.add(kw, value), error);
 }
 
 /// Uses `builder` to assert `value` for `kw` on entity `entid`.
@@ -957,7 +956,7 @@ pub unsafe extern "C" fn entity_builder_add_double<'a, 'c>(
     let builder = &mut *builder;
     let kw = kw_from_string(c_char_to_string(kw));
     let value: TypedValue = value.into();
-    translate_void_result(builder.add_kw(&kw, value), error);
+    translate_void_result(builder.add(kw, value), error);
 }
 
 /// Uses `builder` to assert `value` for `kw` on entity `entid`.
@@ -980,7 +979,7 @@ pub unsafe extern "C" fn entity_builder_add_timestamp<'a, 'c>(
     let builder = &mut *builder;
     let kw = kw_from_string(c_char_to_string(kw));
     let value: TypedValue = TypedValue::instant(value);
-    translate_void_result(builder.add_kw(&kw, value), error);
+    translate_void_result(builder.add(kw, value), error);
 }
 
 /// Uses `builder` to assert `value` for `kw` on entity `entid`.
@@ -1005,7 +1004,7 @@ pub unsafe extern "C" fn entity_builder_add_uuid<'a, 'c>(
     let value = &*value;
     let value = Uuid::from_bytes(value).expect("valid uuid");
     let value: TypedValue = value.into();
-    translate_void_result(builder.add_kw(&kw, value), error);
+    translate_void_result(builder.add(kw, value), error);
 }
 
 /// Uses `builder` to retract `value` for `kw` on entity `entid`.
@@ -1028,7 +1027,7 @@ pub unsafe extern "C" fn entity_builder_retract_string<'a, 'c>(
     let builder = &mut *builder;
     let kw = kw_from_string(c_char_to_string(kw));
     let value: TypedValue = c_char_to_string(value).into();
-    translate_void_result(builder.retract_kw(&kw, value), error);
+    translate_void_result(builder.retract(kw, value), error);
 }
 
 /// Uses `builder` to retract `value` for `kw` on entity `entid`.
@@ -1051,7 +1050,7 @@ pub unsafe extern "C" fn entity_builder_retract_long<'a, 'c>(
     let builder = &mut *builder;
     let kw = kw_from_string(c_char_to_string(kw));
     let value: TypedValue = TypedValue::Long(value);
-    translate_void_result(builder.retract_kw(&kw, value), error);
+    translate_void_result(builder.retract(kw, value), error);
 }
 
 /// Uses `builder` to retract `value` for `kw` on entity `entid`.
@@ -1074,7 +1073,7 @@ pub unsafe extern "C" fn entity_builder_retract_ref<'a, 'c>(
     let builder = &mut *builder;
     let kw = kw_from_string(c_char_to_string(kw));
     let value: TypedValue = TypedValue::Ref(value);
-    translate_void_result(builder.retract_kw(&kw, value), error);
+    translate_void_result(builder.retract(kw, value), error);
 }
 
 /// Uses `builder` to retract `value` for `kw` on entity `entid`.
@@ -1097,7 +1096,7 @@ pub unsafe extern "C" fn entity_builder_retract_keyword<'a, 'c>(
     let builder = &mut *builder;
     let kw = kw_from_string(c_char_to_string(kw));
     let value: TypedValue = kw_from_string(c_char_to_string(value)).into();
-    translate_void_result(builder.retract_kw(&kw, value), error);
+    translate_void_result(builder.retract(kw, value), error);
 }
 
 /// Uses `builder` to retract `value` for `kw` on entity `entid`.
@@ -1120,7 +1119,7 @@ pub unsafe extern "C" fn entity_builder_retract_boolean<'a, 'c>(
     let builder = &mut *builder;
     let kw = kw_from_string(c_char_to_string(kw));
     let value: TypedValue = value.into();
-    translate_void_result(builder.retract_kw(&kw, value), error);
+    translate_void_result(builder.retract(kw, value), error);
 }
 
 /// Uses `builder` to retract `value` for `kw` on entity `entid`.
@@ -1143,7 +1142,7 @@ pub unsafe extern "C" fn entity_builder_retract_double<'a, 'c>(
     let builder = &mut *builder;
     let kw = kw_from_string(c_char_to_string(kw));
     let value: TypedValue = value.into();
-    translate_void_result(builder.retract_kw(&kw, value), error);
+    translate_void_result(builder.retract(kw, value), error);
 }
 
 /// Uses `builder` to retract `value` for `kw` on entity `entid`.
@@ -1166,7 +1165,7 @@ pub unsafe extern "C" fn entity_builder_retract_timestamp<'a, 'c>(
     let builder = &mut *builder;
     let kw = kw_from_string(c_char_to_string(kw));
     let value: TypedValue = TypedValue::instant(value);
-    translate_void_result(builder.retract_kw(&kw, value), error);
+    translate_void_result(builder.retract(kw, value), error);
 }
 
 /// Uses `builder` to retract `value` for `kw` on entity `entid`.
@@ -1192,7 +1191,7 @@ pub unsafe extern "C" fn entity_builder_retract_uuid<'a, 'c>(
     let value = &*value;
     let value = Uuid::from_bytes(value).expect("valid uuid");
     let value: TypedValue = value.into();
-    translate_void_result(builder.retract_kw(&kw, value), error);
+    translate_void_result(builder.retract(kw, value), error);
 }
 
 /// Transacts all the assertions and retractions that have been performed
diff --git a/src/conn.rs b/src/conn.rs
index 9e5ca8d6..eb54dbbf 100644
--- a/src/conn.rs
+++ b/src/conn.rs
@@ -41,6 +41,9 @@ use rusqlite::{
 };
 
 use edn;
+use edn::{
+    InternSet,
+};
 
 use mentat_core::{
     Attribute,
@@ -50,13 +53,12 @@ use mentat_core::{
     Keyword,
     Schema,
     StructuredMap,
+    TxReport,
     TypedValue,
     ValueRc,
     ValueType,
 };
 
-use mentat_core::intern_set::InternSet;
-
 use mentat_db::cache::{
     InProgressCacheTransactWatcher,
     InProgressSQLiteAttributeCache,
@@ -73,7 +75,6 @@ use mentat_db::{
     TransactWatcher,
     TxObservationService,
     TxObserver,
-    TxReport,
 };
 
 use mentat_db::internal_types::TermWithTempIds;
@@ -401,8 +402,8 @@ impl<'a, 'c> InProgress<'a, 'c> {
     /// This exists so you can make your own.
     pub fn transact_builder(&mut self, builder: TermBuilder) -> Result<TxReport> {
         builder.build()
-               .and_then(|(terms, tempid_set)| {
-                    self.transact_terms(terms, tempid_set)
+               .and_then(|(terms, _tempid_set)| {
+                    self.transact_entities(terms)
                })
     }
 
diff --git a/src/entity_builder.rs b/src/entity_builder.rs
index c273b8ca..9ad9d162 100644
--- a/src/entity_builder.rs
+++ b/src/entity_builder.rs
@@ -50,34 +50,27 @@
 //
 // The second is to expose a declarative, programmatic builder pattern for constructing entities.
 //
-// We probably need both, but this file provides the latter. Unfortunately, Entity -- the input to
-// the transactor -- is intimately tied to EDN and to spanned values.
+// We probably need both, but this file provides the latter.
 
-use mentat_core::{
-    HasSchema,
-    KnownEntid,
-    Keyword,
-    TypedValue,
+use edn::{
+    InternSet,
+    PlainSymbol,
+    ValueRc,
 };
-
-use mentat_core::intern_set::InternSet;
-use mentat_core::util::Either;
-
-use mentat_db::{
-    TxReport,
-};
-
-use mentat_db::internal_types::{
-    KnownEntidOr,
-    TempIdHandle,
-    Term,
-    TermWithTempIds,
-    TypedValueOr,
-};
-
 use edn::entities::{
+    AttributePlace,
+    Entity,
+    EntityPlace,
+    LookupRef,
     OpType,
     TempId,
+    TxFunction,
+    ValuePlace,
+};
+
+use mentat_core::{
+    TxReport,
+    TypedValue,
 };
 
 use conn::{
@@ -85,66 +78,65 @@ use conn::{
 };
 
 use errors::{
-    MentatError,
     Result,
 };
 
-pub type Terms = (Vec<TermWithTempIds>, InternSet<TempId>);
+pub type Terms = (Vec<Entity<TypedValue>>, InternSet<TempId>);
 
 pub struct TermBuilder {
     tempids: InternSet<TempId>,
-    terms: Vec<TermWithTempIds>,
+    terms: Vec<Entity<TypedValue>>,
 }
 
 pub struct EntityBuilder<T: BuildTerms + Sized> {
     builder: T,
-    entity: KnownEntidOr<TempIdHandle>,
+    entity: EntityPlace<TypedValue>,
 }
 
 pub trait BuildTerms where Self: Sized {
-    fn named_tempid(&mut self, name: String) -> TempIdHandle;
+    fn named_tempid<I>(&mut self, name: I) -> ValueRc<TempId> where I: Into<String>;
     fn describe_tempid(self, name: &str) -> EntityBuilder<Self>;
-    fn describe<E>(self, entity: E) -> EntityBuilder<Self> where E: IntoThing<KnownEntidOr<TempIdHandle>>;
-    fn add<E, V>(&mut self, e: E, a: KnownEntid, v: V) -> Result<()>
-    where E: IntoThing<KnownEntidOr<TempIdHandle>>,
-          V: IntoThing<TypedValueOr<TempIdHandle>>;
-    fn retract<E, V>(&mut self, e: E, a: KnownEntid, v: V) -> Result<()>
-    where E: IntoThing<KnownEntidOr<TempIdHandle>>,
-          V: IntoThing<TypedValueOr<TempIdHandle>>;
+    fn describe<E>(self, entity: E) -> EntityBuilder<Self> where E: Into<EntityPlace<TypedValue>>;
+    fn add<E, A, V>(&mut self, e: E, a: A, v: V) -> Result<()>
+    where E: Into<EntityPlace<TypedValue>>,
+          A: Into<AttributePlace>,
+          V: Into<ValuePlace<TypedValue>>;
+    fn retract<E, A, V>(&mut self, e: E, a: A, v: V) -> Result<()>
+    where E: Into<EntityPlace<TypedValue>>,
+          A: Into<AttributePlace>,
+          V: Into<ValuePlace<TypedValue>>;
 }
 
 impl BuildTerms for TermBuilder {
-    fn named_tempid(&mut self, name: String) -> TempIdHandle {
-        self.tempids.intern(TempId::External(name))
+    fn named_tempid<I>(&mut self, name: I) -> ValueRc<TempId> where I: Into<String> {
+        self.tempids.intern(TempId::External(name.into()))
     }
 
     fn describe_tempid(mut self, name: &str) -> EntityBuilder<Self> {
-        let e = self.named_tempid(name.into());
+        let e = self.named_tempid(name);
         self.describe(e)
     }
 
-    fn describe<E>(self, entity: E) -> EntityBuilder<Self> where E: IntoThing<KnownEntidOr<TempIdHandle>> {
+    fn describe<E>(self, entity: E) -> EntityBuilder<Self> where E: Into<EntityPlace<TypedValue>> {
         EntityBuilder {
             builder: self,
-            entity: entity.into_thing(),
+            entity: entity.into(),
         }
     }
 
-    fn add<E, V>(&mut self, e: E, a: KnownEntid, v: V) -> Result<()>
-    where E: IntoThing<KnownEntidOr<TempIdHandle>>,
-          V: IntoThing<TypedValueOr<TempIdHandle>> {
-        let e = e.into_thing();
-        let v = v.into_thing();
-        self.terms.push(Term::AddOrRetract(OpType::Add, e, a.into(), v));
+    fn add<E, A, V>(&mut self, e: E, a: A, v: V) -> Result<()>
+    where E: Into<EntityPlace<TypedValue>>,
+          A: Into<AttributePlace>,
+          V: Into<ValuePlace<TypedValue>> {
+        self.terms.push(Entity::AddOrRetract { op: OpType::Add, e: e.into(), a: a.into(), v: v.into() });
         Ok(())
     }
 
-    fn retract<E, V>(&mut self, e: E, a: KnownEntid, v: V) -> Result<()>
-    where E: IntoThing<KnownEntidOr<TempIdHandle>>,
-          V: IntoThing<TypedValueOr<TempIdHandle>> {
-        let e = e.into_thing();
-        let v = v.into_thing();
-        self.terms.push(Term::AddOrRetract(OpType::Retract, e, a.into(), v));
+    fn retract<E, A, V>(&mut self, e: E, a: A, v: V) -> Result<()>
+    where E: Into<EntityPlace<TypedValue>>,
+          A: Into<AttributePlace>,
+          V: Into<ValuePlace<TypedValue>> {
+        self.terms.push(Entity::AddOrRetract { op: OpType::Retract, e: e.into(), a: a.into(), v: v.into() });
         Ok(())
     }
 }
@@ -166,23 +158,35 @@ impl TermBuilder {
     }
 
     #[allow(dead_code)]
-    pub fn numbered_tempid(&mut self, id: i64) -> TempIdHandle {
+    pub fn numbered_tempid(&mut self, id: i64) -> ValueRc<TempId> {
         self.tempids.intern(TempId::Internal(id))
     }
+
+    pub fn lookup_ref<A, V>(a: A, v: V) -> LookupRef<TypedValue>
+    where A: Into<AttributePlace>,
+          V: Into<TypedValue> {
+        LookupRef { a: a.into(), v: v.into() }
+    }
+
+    pub fn tx_function(op: &str) -> TxFunction {
+        TxFunction { op: PlainSymbol::plain(op) }
+    }
 }
 
 impl<T> EntityBuilder<T> where T: BuildTerms {
-    pub fn finish(self) -> (T, KnownEntidOr<TempIdHandle>) {
+    pub fn finish(self) -> (T, EntityPlace<TypedValue>) {
         (self.builder, self.entity)
     }
 
-    pub fn add<V>(&mut self, a: KnownEntid, v: V) -> Result<()>
-    where V: IntoThing<TypedValueOr<TempIdHandle>> {
+    pub fn add<A, V>(&mut self, a: A, v: V) -> Result<()>
+    where A: Into<AttributePlace>,
+          V: Into<ValuePlace<TypedValue>> {
         self.builder.add(self.entity.clone(), a, v)
     }
 
-    pub fn retract<V>(&mut self, a: KnownEntid, v: V) -> Result<()>
-    where V: IntoThing<TypedValueOr<TempIdHandle>> {
+    pub fn retract<A, V>(&mut self, a: A, v: V) -> Result<()>
+    where A: Into<AttributePlace>,
+          V: Into<ValuePlace<TypedValue>> {
         self.builder.retract(self.entity.clone(), a, v)
     }
 }
@@ -207,8 +211,8 @@ impl<'a, 'c> InProgressBuilder<'a, 'c> {
         let mut in_progress = self.in_progress;
         let result = self.builder
                          .build()
-                         .and_then(|(terms, tempid_set)| {
-                             in_progress.transact_terms(terms, tempid_set)
+                         .and_then(|(terms, _tempid_set)| {
+                             in_progress.transact_entities(terms)
                          });
         (in_progress, result)
     }
@@ -226,79 +230,38 @@ impl<'a, 'c> InProgressBuilder<'a, 'c> {
 }
 
 impl<'a, 'c> BuildTerms for InProgressBuilder<'a, 'c> {
-    fn named_tempid(&mut self, name: String) -> TempIdHandle {
+    fn named_tempid<I>(&mut self, name: I) -> ValueRc<TempId> where I: Into<String> {
         self.builder.named_tempid(name)
     }
 
     fn describe_tempid(mut self, name: &str) -> EntityBuilder<InProgressBuilder<'a, 'c>> {
-        let e = self.builder.named_tempid(name.into());
+        let e = self.builder.named_tempid(name.to_string());
         self.describe(e)
     }
 
-    fn describe<E>(self, entity: E) -> EntityBuilder<InProgressBuilder<'a, 'c>> where E: IntoThing<KnownEntidOr<TempIdHandle>> {
+    fn describe<E>(self, entity: E) -> EntityBuilder<InProgressBuilder<'a, 'c>> where E: Into<EntityPlace<TypedValue>> {
         EntityBuilder {
             builder: self,
-            entity: entity.into_thing(),
+            entity: entity.into(),
         }
     }
 
-    fn add<E, V>(&mut self, e: E, a: KnownEntid, v: V) -> Result<()>
-    where E: IntoThing<KnownEntidOr<TempIdHandle>>,
-          V: IntoThing<TypedValueOr<TempIdHandle>> {
+    fn add<E, A, V>(&mut self, e: E, a: A, v: V) -> Result<()>
+    where E: Into<EntityPlace<TypedValue>>,
+          A: Into<AttributePlace>,
+          V: Into<ValuePlace<TypedValue>> {
         self.builder.add(e, a, v)
     }
 
-    fn retract<E, V>(&mut self, e: E, a: KnownEntid, v: V) -> Result<()>
-    where E: IntoThing<KnownEntidOr<TempIdHandle>>,
-          V: IntoThing<TypedValueOr<TempIdHandle>> {
+    fn retract<E, A, V>(&mut self, e: E, a: A, v: V) -> Result<()>
+    where E: Into<EntityPlace<TypedValue>>,
+          A: Into<AttributePlace>,
+          V: Into<ValuePlace<TypedValue>> {
         self.builder.retract(e, a, v)
     }
 }
 
-impl<'a, 'c> InProgressBuilder<'a, 'c> {
-    pub fn add_kw<E, V>(&mut self, e: E, a: &Keyword, v: V) -> Result<()>
-    where E: IntoThing<KnownEntidOr<TempIdHandle>>,
-          V: IntoThing<TypedValueOr<TempIdHandle>> {
-        let (attribute, value) = self.extract_kw_value(a, v.into_thing())?;
-        self.add(e, attribute, value)
-    }
-
-    pub fn retract_kw<E, V>(&mut self, e: E, a: &Keyword, v: V) -> Result<()>
-    where E: IntoThing<KnownEntidOr<TempIdHandle>>,
-          V: IntoThing<TypedValueOr<TempIdHandle>> {
-        let (attribute, value) = self.extract_kw_value(a, v.into_thing())?;
-        self.retract(e, attribute, value)
-    }
-
-    fn extract_kw_value(&mut self, a: &Keyword, v: TypedValueOr<TempIdHandle>) -> Result<(KnownEntid, TypedValueOr<TempIdHandle>)> {
-        let attribute: KnownEntid;
-        if let Some((attr, aa)) = self.in_progress.attribute_for_ident(a) {
-            if let Either::Left(ref tv) = v {
-                let provided = tv.value_type();
-                let expected = attr.value_type;
-                if provided != expected {
-                    bail!(MentatError::ValueTypeMismatch(provided, expected));
-                }
-            }
-            attribute = aa;
-        } else {
-            bail!(MentatError::UnknownAttribute(a.to_string()));
-        }
-        Ok((attribute, v))
-    }
-}
-
 impl<'a, 'c> EntityBuilder<InProgressBuilder<'a, 'c>> {
-    pub fn add_kw<V>(&mut self, a: &Keyword, v: V) -> Result<()>
-    where V: IntoThing<TypedValueOr<TempIdHandle>> {
-        self.builder.add_kw(self.entity.clone(), a, v)
-    }
-
-    pub fn retract_kw<V>(&mut self, a: &Keyword, v: V) -> Result<()>
-    where V: IntoThing<TypedValueOr<TempIdHandle>> {
-        self.builder.retract_kw(self.entity.clone(), a, v)
-    }
-
     /// Build the terms from this builder and transact them against the current
     /// `InProgress`. This method _always_ returns the `InProgress` -- failure doesn't
     /// imply an automatic rollback.
@@ -313,69 +276,6 @@ impl<'a, 'c> EntityBuilder<InProgressBuilder<'a, 'c>> {
     }
 }
 
-// Can't implement Into for Rc<T>.
-pub trait IntoThing<T>: Sized {
-    fn into_thing(self) -> T;
-}
-
-pub trait FromThing<T> {
-    fn from_thing(v: T) -> Self;
-}
-
-impl<T> FromThing<T> for T {
-    fn from_thing(v: T) -> T {
-        v
-    }
-}
-
-impl<I, F> IntoThing<I> for F where I: FromThing<F> {
-    fn into_thing(self) -> I {
-        I::from_thing(self)
-    }
-}
-
-impl<'a> FromThing<&'a TempIdHandle> for TypedValueOr<TempIdHandle> {
-    fn from_thing(v: &'a TempIdHandle) -> Self {
-        Either::Right(v.clone())
-    }
-}
-
-impl FromThing<TempIdHandle> for TypedValueOr<TempIdHandle> {
-    fn from_thing(v: TempIdHandle) -> Self {
-        Either::Right(v)
-    }
-}
-
-impl FromThing<TypedValue> for TypedValueOr<TempIdHandle> {
-    fn from_thing(v: TypedValue) -> Self {
-        Either::Left(v)
-    }
-}
-
-impl FromThing<TempIdHandle> for KnownEntidOr<TempIdHandle> {
-    fn from_thing(v: TempIdHandle) -> Self {
-        Either::Right(v)
-    }
-}
-
-impl<'a> FromThing<&'a KnownEntid> for KnownEntidOr<TempIdHandle> {
-    fn from_thing(v: &'a KnownEntid) -> Self {
-        Either::Left(v.clone())
-    }
-}
-
-impl FromThing<KnownEntid> for KnownEntidOr<TempIdHandle> {
-    fn from_thing(v: KnownEntid) -> Self {
-        Either::Left(v)
-    }
-}
-
-impl FromThing<KnownEntid> for TypedValueOr<TempIdHandle> {
-    fn from_thing(v: KnownEntid) -> Self {
-        Either::Left(v.into())
-    }
-}
-
 #[cfg(test)]
 mod testing {
     extern crate mentat_db;
@@ -384,9 +284,11 @@ mod testing {
         Conn,
         Entid,
         HasSchema,
+        KnownEntid,
+        MentatError,
         Queryable,
-        TypedValue,
         TxReport,
+        TypedValue,
     };
 
     use super::*;
@@ -399,7 +301,7 @@ mod testing {
     #[test]
     fn test_entity_builder_bogus_entids() {
         let mut builder = TermBuilder::new();
-        let e = builder.named_tempid("x".into());
+        let e = builder.named_tempid("x");
         let a1 = fake_known_entid(37);    // :db/doc
         let a2 = fake_known_entid(999);
         let v = TypedValue::typed_string("Some attribute");
@@ -419,7 +321,7 @@ mod testing {
         let mut in_progress = conn.begin_transaction(&mut sqlite).expect("begun successfully");
 
         // This should fail: unrecognized entid.
-        match in_progress.transact_terms(terms, tempids).expect_err("expected transact to fail") {
+        match in_progress.transact_entities(terms).expect_err("expected transact to fail") {
             MentatError::DbError(e) => {
                 assert_eq!(e.kind(), mentat_db::DbErrorKind::UnrecognizedEntid(999));
             },
@@ -451,10 +353,10 @@ mod testing {
         let a_many = in_progress.get_entid(&kw!(:foo/many)).expect(":foo/many");
 
         let mut builder = in_progress.builder();
-        let e_x = builder.named_tempid("x".into());
+        let e_x = builder.named_tempid("x");
         let v_many_1 = TypedValue::typed_string("Some text");
         let v_many_2 = TypedValue::typed_string("Other text");
-        builder.add_kw(e_x.clone(), &kw!(:foo/many), v_many_1).expect("add succeeded");
+        builder.add(e_x.clone(), kw!(:foo/many), v_many_1).expect("add succeeded");
         builder.add(e_x.clone(), a_many, v_many_2).expect("add succeeded");
         builder.commit().expect("commit succeeded");
     }
@@ -489,8 +391,8 @@ mod testing {
             // Scoped borrow of in_progress.
             {
                 let mut builder = TermBuilder::new();
-                let e_x = builder.named_tempid("x".into());
-                let e_y = builder.named_tempid("y".into());
+                let e_x = builder.named_tempid("x");
+                let e_y = builder.named_tempid("y");
                 let a_ref = in_progress.get_entid(&foo_ref).expect(":foo/ref");
                 let a_one = in_progress.get_entid(&foo_one).expect(":foo/one");
                 let a_many = in_progress.get_entid(&foo_many).expect(":foo/many");
@@ -508,7 +410,7 @@ mod testing {
                 assert_eq!(tempids.len(), 2);
                 assert_eq!(terms.len(), 4);
 
-                report = in_progress.transact_terms(terms, tempids).expect("add succeeded");
+                report = in_progress.transact_entities(terms).expect("add succeeded");
                 let x = report.tempids.get("x").expect("our tempid has an ID");
                 let y = report.tempids.get("y").expect("our tempid has an ID");
                 assert_eq!(in_progress.lookup_value_for_attribute(*y, &foo_ref).expect("lookup succeeded"),
diff --git a/src/lib.rs b/src/lib.rs
index b8e83cd2..f1da47a9 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -41,6 +41,7 @@ pub use mentat_core::{
     Keyword,
     Schema,
     Binding,
+    TxReport,
     TypedValue,
     Uuid,
     Utc,
@@ -56,7 +57,6 @@ pub use mentat_db::{
     DB_SCHEMA_CORE,
     AttributeSet,
     TxObserver,
-    TxReport,
     new_connection,
 };
 
diff --git a/src/store.rs b/src/store.rs
index 21bad12c..1cfce8bc 100644
--- a/src/store.rs
+++ b/src/store.rs
@@ -30,12 +30,12 @@ use mentat_core::{
     Entid,
     Keyword,
     StructuredMap,
+    TxReport,
     TypedValue,
     ValueRc,
 };
 use mentat_db::{
     TxObserver,
-    TxReport,
 };
 
 use mentat_tolstoy::Syncer;
@@ -607,12 +607,12 @@ mod tests {
                 let name = format!("todo{}", i);
                 let uuid = Uuid::new_v4();
                 let mut builder = in_progress.builder().describe_tempid(&name);
-                builder.add_kw(&kw!(:todo/uuid), TypedValue::Uuid(uuid)).expect("Expected added uuid");
+                builder.add(kw!(:todo/uuid), TypedValue::Uuid(uuid)).expect("Expected added uuid");
                 changeset.insert(uuid_entid.clone());
-                builder.add_kw(&kw!(:todo/name), TypedValue::typed_string(&name)).expect("Expected added name");
+                builder.add(kw!(:todo/name), TypedValue::typed_string(&name)).expect("Expected added name");
                 changeset.insert(name_entid.clone());
                 if i % 2 == 0 {
-                    builder.add_kw(&kw!(:todo/completion_date), TypedValue::current_instant()).expect("Expected added date");
+                    builder.add(kw!(:todo/completion_date), TypedValue::current_instant()).expect("Expected added date");
                     changeset.insert(date_entid.clone());
                 }
                 let (ip, r) = builder.transact();
@@ -622,8 +622,8 @@ mod tests {
                 in_progress = ip;
             }
             let mut builder = in_progress.builder().describe_tempid("Label");
-            builder.add_kw(&kw!(:label/name), TypedValue::typed_string("Label 1")).expect("Expected added name");
-            builder.add_kw(&kw!(:label/color), TypedValue::typed_string("blue")).expect("Expected added color");
+            builder.add(kw!(:label/name), TypedValue::typed_string("Label 1")).expect("Expected added name");
+            builder.add(kw!(:label/color), TypedValue::typed_string("blue")).expect("Expected added color");
             builder.commit().expect("expect transaction to occur");
         }
 
@@ -678,8 +678,8 @@ mod tests {
             for i in 0..3 {
                 let name = format!("label{}", i);
                 let mut builder = in_progress.builder().describe_tempid(&name);
-                builder.add_kw(&kw!(:label/name), TypedValue::typed_string(&name)).expect("Expected added name");
-                builder.add_kw(&kw!(:label/color), TypedValue::typed_string("blue")).expect("Expected added color");
+                builder.add(kw!(:label/name), TypedValue::typed_string(&name)).expect("Expected added name");
+                builder.add(kw!(:label/color), TypedValue::typed_string("blue")).expect("Expected added color");
                 let (ip, _) = builder.transact();
                 in_progress = ip;
             }
diff --git a/src/vocabulary.rs b/src/vocabulary.rs
index 7e622ee2..42674b5b 100644
--- a/src/vocabulary.rs
+++ b/src/vocabulary.rs
@@ -812,14 +812,14 @@ impl VocabularySource for SimpleVocabularySource {
 impl<'a, 'c> VocabularyMechanics for InProgress<'a, 'c> {
     /// Turn the vocabulary into datoms, transact them, and on success return the outcome.
     fn install_vocabulary(&mut self, definition: &Definition) -> Result<VocabularyOutcome> {
-        let (terms, tempids) = definition.description(self)?;
-        self.transact_terms(terms, tempids)?;
+        let (terms, _tempids) = definition.description(self)?;
+        self.transact_entities(terms)?;
         Ok(VocabularyOutcome::Installed)
     }
 
     fn install_attributes_for<'definition>(&mut self, definition: &'definition Definition, attributes: Vec<&'definition (Keyword, Attribute)>) -> Result<VocabularyOutcome> {
-        let (terms, tempids) = definition.description_for_attributes(&attributes, self, None)?;
-        self.transact_terms(terms, tempids)?;
+        let (terms, _tempids) = definition.description_for_attributes(&attributes, self, None)?;
+        self.transact_entities(terms)?;
         Ok(VocabularyOutcome::InstalledMissingAttributes)
     }
 
@@ -834,8 +834,8 @@ impl<'a, 'c> VocabularyMechanics for InProgress<'a, 'c> {
 
         // TODO: don't do work for attributes that are unchanged. Here we rely on the transactor
         // to elide duplicate datoms.
-        let (terms, tempids) = definition.description_diff(self, &from_version)?;
-        self.transact_terms(terms, tempids)?;
+        let (terms, _tempids) = definition.description_diff(self, &from_version)?;
+        self.transact_entities(terms)?;
 
         definition.post(self, &from_version)?;
         Ok(VocabularyOutcome::Upgraded)