diff --git a/README.md b/README.md
--- a/README.md
+++ b/README.md
@@ -1,5 +1,18 @@
 # Ribbit
 
+- [Ribbit](#ribbit)
+    - [Status](#status)
+        - [Current Features](#current-features)
+            - [Basic @Select .. From ..](#basic-select--from-)
+            - [Cross product](#cross-product)
+            - [Limited Conditionals](#limited-conditionals)
+    - [Roadmap](#roadmap)
+        - [More conditional operatores.](#more-conditional-operatores)
+        - [`CREATE TABLE` support.](#create-table-support)
+        - [`INSERT INTO` support.](#insert-into-support)
+    - [How it compares with other libraries.](#how-it-compares-with-other-libraries)
+    - [The name: Ribbit](#the-name-ribbit)
+
 Ribbit is yet another type safe relational database
 library for Haskell, heavily inspired by the amazing
 [Servant](http://hackage.haskell.org/package/servant) library. The goal
@@ -31,9 +44,60 @@
 
 ## Status
 
-The status of Ribbit is non-functional pre-alpha. My goal though is to
-make sure it is absolutely production ready for the operations it ends
-up supporting, but we are a long way from that at the moment.
+The status of Ribbit "Very Incomplete". My goal is to take a "depth first"
+approach, where every feature added is production ready before moving on to the
+next feature. Featured back-ends include `postgres-simple` at this time.
+
+### Current Features
+
+These are the features that are currently implemented.
+
+#### Basic @Select .. From ..
+
+We support queries of the form:
+
+> type MyQuery = Select '["field1", "field2"] `From` MyTable
+
+#### Cross product
+
+We support queries of the form:
+
+type MyQuery = Select '["t1.field1", "t2.field2"] `From` MyTable1 `As` "t1" `X` MyTable2 `As` "t2"
+
+#### Limited Conditionals
+
+We support queries of the form:
+
+> type MyQuery = Select '["field1", "field2"] `From` MyTable `Where` <condition>
+
+Where <condition> can include:
+
+- a `And` b: Basic intersection.
+- a `Or` b: Basic union.
+- "field" `Equals` (?): Test for equality. This introduces a query parameter that must be supplied at runtime.
+- "field1" `Equals` "field2": Test the equality of two fields (that both must exist in the schema)
+
+## Roadmap
+
+This is what I plan to work on next:
+
+### More conditional operatores.
+
+I want to fill in the conditional operators with the usual suspects (`<`, `<=`, `>`, `>=`, `!=`, etc.).
+
+### `CREATE TABLE` support.
+
+One source of programming bugs is when the schema in the database and the
+schema described by your schema types get out of sync. It is never possible to
+always ensure at compile time that your database will match your program when
+actually run, but the addition of `CREATE TABLE` support will at least make it
+possible for the database schema to have one source of truth in your codebase
+(as opposed to having to maintain Ribbit schemas and also a corresponding
+schema embedded in some database initialization script somewhere).
+
+### `INSERT INTO` support.
+
+Obviously, we want to do more with our DB than just read from it.
 
 ## How it compares with other libraries.
 
diff --git a/ribbit.cabal b/ribbit.cabal
--- a/ribbit.cabal
+++ b/ribbit.cabal
@@ -1,6 +1,6 @@
 
 name:                ribbit
-version:             0.2.0.0
+version:             0.2.0.1
 synopsis:            ribbit
 -- description:         
 homepage:            https://github.com/owensmurray/ribbit
@@ -23,7 +23,6 @@
   build-depends:
     Only              >= 0.1     && < 0.2,
     base              >= 4.12    && < 4.13,
-    om-show           >= 0.1.1.0 && < 0.2,
     postgresql-simple >= 0.6.2   && < 0.7,
     text              >= 1.2.3.1 && < 1.3
   hs-source-dirs:      src
diff --git a/src/Database/Ribbit.hs b/src/Database/Ribbit.hs
--- a/src/Database/Ribbit.hs
+++ b/src/Database/Ribbit.hs
@@ -61,6 +61,7 @@
 import Data.String (IsString, fromString)
 import Data.Text (Text)
 import Data.Tuple.Only (Only)
+import Data.Type.Bool (If, type (||))
 import GHC.TypeLits (KnownSymbol, TypeError, ErrorMessage((:<>:),
   (:$$:), ShowType), AppendSymbol, Symbol)
 import qualified GHC.TypeLits as Lit
@@ -153,13 +154,10 @@
 --
 
 
-
-
 {- | "SELECT" combinator, used for starting a @SELECT@ statement. -}
 data Select fields
 
 
-
 {- |
   "FROM" combinator, used for attaching a SELECT projection to a relation
   in the database.
@@ -173,7 +171,6 @@
 infixl 6 `Where`
 
 
-
 {- | "=" combinator for conditions. -}
 data Equals l r
 infix 9 `Equals`
@@ -220,18 +217,18 @@
 data Expr a
 
 type family ProjectionType proj schema where
-  ProjectionType '[name] (Field name typ) = Only typ
-  ProjectionType '[name] (Field name2 typ) =
-    TypeError (
-      'Lit.Text "name ("
-      ':<>: 'ShowType name
-      ':<>: 'Lit.Text ") not found in relation."
-    )
-  ProjectionType '[name] (Field name typ :> _) = Only typ
-  ProjectionType '[name] (_ :> more) = ProjectionType '[name] more
+  ProjectionType '[name] schema =
+    LookupType name schema schema
+  ProjectionType (name:more) schema =
+    LookupType name schema schema
+    :> ProjectionType more schema
 
-  ProjectionType (name:more) relation =
-    ProjectionType '[name] relation :> ProjectionType more relation
+type family LookupType name schema context where
+  LookupType name (Field name typ) _ = Only typ
+  LookupType name (Field name typ :> _) _ = Only typ
+  LookupType name (Field _ typ) context = NotInSchema name context
+  LookupType name (_ :> more) context = LookupType name more context
+  LookupType name a context = NotInSchema name context
 
 class Table relation where
   type DBSchema relation
@@ -292,7 +289,28 @@
     StripUnit (Flatten (ArgsType (schema, a) :> ArgsType (schema, b)))
   ArgsType (schema, Equals field (?)) =
     ProjectionType '[field] schema
+  ArgsType (schema, Equals field expr) =
+    If
+      (ValidField expr schema)
+      (If (ValidField field schema) () (NotInSchema field schema))
+      (NotInSchema expr schema)
   ArgsType _ = ()
+
+type family NotInSchema field schema where
+  NotInSchema field schema =
+    TypeError (
+      'Lit.Text "name ("
+      ':<>: 'ShowType field
+      ':<>: 'Lit.Text ") not found in schema: "
+      ':<>: 'ShowType schema
+    )
+
+
+{- | Produce a type error if the field is not contained within the schema. -}
+type family ValidField field schema where
+  ValidField name (Field name typ) = 'True
+  ValidField name (Field _ typ) = 'False
+  ValidField name (a :> b) = ValidField name a || ValidField name b
 
 
 {- |
diff --git a/src/Database/Ribbit/PostgreSQL.hs b/src/Database/Ribbit/PostgreSQL.hs
--- a/src/Database/Ribbit/PostgreSQL.hs
+++ b/src/Database/Ribbit/PostgreSQL.hs
@@ -61,6 +61,9 @@
   toRow (a :> b) = toRow a ++ toRow b
 instance (ToField a) => ToRow (Only a) where
   toRow = PGT.toRow
+instance ToRow () where
+  toRow = PGT.toRow
+  
 
 
 {- | Wrapper that helps us avoid orphan instances. -}