diff --git a/changelog b/changelog
--- a/changelog
+++ b/changelog
@@ -1,3 +1,7 @@
+1.2.1
+
+* Updates to documentation.
+
 1.2.0
 
 * Add Validator e p x a profunctor transformer newtype with instances
diff --git a/validation.cabal b/validation.cabal
--- a/validation.cabal
+++ b/validation.cabal
@@ -1,5 +1,5 @@
 name:               validation
-version:            1.2.0
+version:            1.2.1
 license:            BSD3
 license-file:       LICENCE
 author:             Tony Morris <ʇǝu˙sıɹɹoɯʇ@ןןǝʞsɐɥ> <dibblego>, Nick Partridge <nkpart>
@@ -13,30 +13,53 @@
 description:
   <<https://logo.systemf.com.au/systemf-450x450.png>>
   .
-  A data-type like Either but with differing properties and type-class
-  instances.
-  .
-  Library support is provided for this different representation, include
-  `lens`-related functions for converting between each and abstracting over their
-  similarities.
+  A data type like @Either@ but with an accumulating @Applicative@ instance.
   .
-  * `Validation`
+  == @Validation@
   .
-  The `Validation` data type is isomorphic to `Either`, but has an instance
-  of `Applicative` that accumulates on the error side. That is to say, if two
-  (or more) errors are encountered, they are appended using a `Semigroup`
+  The @Validation@ data type is isomorphic to @Either@, but has an instance
+  of @Applicative@ that accumulates on the error side. That is to say, if two
+  (or more) errors are encountered, they are appended using a @Semigroup@
   operation.
   .
-  As a consequence of this `Applicative` instance, there is no corresponding
-  `Bind` or `Monad` instance. `Validation` is an example of, "An applicative
+  As a consequence of this @Applicative@ instance, there is no corresponding
+  @Bind@ or @Monad@ instance. @Validation@ is an example of, "An applicative
   functor that is not a monad."
+  .
+  The library provides:
+  .
+  * Classy optics (@GetValidation@, @HasValidation@, @ReviewValidation@,
+    @AsValidation@, and corresponding classes for @Failure@ and @Success@)
+    following the conventions of @makeClassy@ and @makeClassyPrisms@ from @lens@.
+  * Polymorphic prisms (@__Failure@, @__Success@) for type-changing operations.
+  * Isomorphisms to @Either@ and @(Bool, a)@.
+  .
+  == @Validator@
+  .
+  The @Validator@ newtype is a profunctor transformer:
+  .
+  @newtype Validator e p x a = Validator (p x (Validation e a))@
+  .
+  @Validator e (->) x a@ is isomorphic to @x -> Validation e a@. The profunctor
+  parameter @p@ generalises this to other optic-like contexts such as @Tagged@,
+  @Iso@, and @Prism@.
+  .
+  Instances include @Functor@, @Apply@, @Applicative@, @Alt@, @Selective@,
+  @Profunctor@, @Strong@, @Choice@, @Semigroupoid@, @Category@, @Arrow@,
+  @ArrowApply@, @ArrowChoice@, and @Wrapped@.
+  .
+  The @Applicative@ instance accumulates errors in parallel (using @Semigroup@),
+  while @Category@ composition short-circuits on @Failure@ (like monadic bind).
+  .
+  The library also provides profunctor newtype wrappers (@Iso''@, @Prism''@) that
+  allow @Validator@ to be parameterised over monomorphic isos and prisms.
 
 homepage:           https://github.com/system-f/validation
 bug-reports:        https://github.com/system-f/validation/issues
 cabal-version:      >= 1.10
 build-type:         Simple
 extra-source-files: changelog
-tested-with:        GHC==9.0.1, GHC==8.10.4, GHC==8.8.4, GHC==8.6.5, GHC==8.4.4
+tested-with:        GHC == 9.10.3, GHC == 9.8.4, GHC == 9.6.7, GHC==9.0.1, GHC==8.10.4, GHC==8.8.4, GHC==8.6.5, GHC==8.4.4
 
 source-repository   head
   type:             git
@@ -107,6 +130,7 @@
   build-depends:
                       base       >= 4.11   && < 5
                     , process    >= 1.6    && < 2
+                    , validation
 
   ghc-options:
                     -Wall