diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5aa26d2..c3e3d3b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,4 +1,4 @@
-## 0.1.0 (Unreleased)
+## 0.1.0 (2022-05-16)
 Initial release.
 
   * basic instances (lists, numerics)
diff --git a/README.md b/README.md
index 37249ac..1a848aa 100644
--- a/README.md
+++ b/README.md
@@ -1,2 +1,24 @@
 # strongweak
-TODO
+Definitions for transforming between types.
+
+  * `strong -> weak` drops invariants (e.g. going from a bounded to an unbounded
+    numeric type)
+  * `weak -> Maybe strong` introduces invariants
+
+This is not a `Convertible` library that enumerates transformations between
+types into a dictionary.
+
+  * A "strong" type has exactly one "weak" representation.
+  * Weakening a type is safe.
+  * Strengthening a type may fail.
+
+There are generic derivers for generating `Strengthen` and `Weaken` instances
+for arbitrary data types. The `Strengthen` instances annotate errors
+extensively, telling you the datatype & record for which strengthening failed -
+recursively, for nested types.
+
+This is a validation library. We don't fail on the first error -- we attempt to
+validate every part of a data type, and collate the errors into a list. This
+happens magically in the generic deriver, but if you're writing your own
+instances, you may want `ApplicativeDo` so you can use do notation. So it'll
+monadic, but actually everything will get checked.
diff --git a/package.yaml b/package.yaml
index 64edfc7..43b6157 100644
--- a/package.yaml
+++ b/package.yaml
@@ -67,8 +67,8 @@ dependencies:
 - base >= 4.14 && < 5
 - vector-sized ^>= 1.5.0
 - refined ^>= 0.6.3
-- prettyprinter # TODO
-- validation
+- prettyprinter ^>= 1.7.1
+- validation ^>= 1.1.2
 
 library:
   source-dirs: src
diff --git a/strongweak.cabal b/strongweak.cabal
index 1904c9c..1ff7d88 100644
--- a/strongweak.cabal
+++ b/strongweak.cabal
@@ -75,8 +75,8 @@ library
   ghc-options: -Wall
   build-depends:
       base >=4.14 && <5
-    , prettyprinter
+    , prettyprinter >=1.7.1 && <1.8
     , refined >=0.6.3 && <0.7
-    , validation
+    , validation >=1.1.2 && <1.2
     , vector-sized >=1.5.0 && <1.6
   default-language: Haskell2010