diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,7 @@
+## v1.4.0.1 (???)
+
+* Allow base-4.10
+
 ## [v1.4](https://github.com/diagrams/diagrams-core/tree/v1.4) (2016-10-26)
 
 * **New features**
diff --git a/diagrams-core.cabal b/diagrams-core.cabal
--- a/diagrams-core.cabal
+++ b/diagrams-core.cabal
@@ -1,5 +1,5 @@
 Name:                diagrams-core
-Version:             1.4
+Version:             1.4.0.1
 Synopsis:            Core libraries for diagrams EDSL
 Description:         The core modules underlying diagrams,
                      an embedded domain-specific language
@@ -12,7 +12,7 @@
 Bug-reports:         https://github.com/diagrams/diagrams-core/issues
 Category:            Graphics
 Build-type:          Simple
-Cabal-version:       >=1.10
+Cabal-version:       >=1.18
 Extra-source-files:  CHANGELOG.md, README.markdown, diagrams/*.svg
 extra-doc-files:     diagrams/*.svg
 Tested-with:         GHC == 7.6.3, GHC == 7.8.4, GHC == 7.10.2, GHC == 8.0.1
@@ -36,7 +36,7 @@
                        Diagrams.Core.Types,
                        Diagrams.Core.V
 
-  Build-depends:       base >= 4.2 && < 4.10,
+  Build-depends:       base >= 4.2 && < 4.11,
                        containers >= 0.4.2 && < 0.6,
                        unordered-containers >= 0.2 && < 0.3,
                        semigroups >= 0.8.4 && < 0.19,
diff --git a/src/Diagrams/Core/Envelope.hs b/src/Diagrams/Core/Envelope.hs
--- a/src/Diagrams/Core/Envelope.hs
+++ b/src/Diagrams/Core/Envelope.hs
@@ -107,7 +107,7 @@
 --
 --   The idea for envelopes came from
 --   Sebastian Setzer; see
---   <http://byorgey.wordpress.com/2009/10/28/collecting-attributes/#comment-2030>.  See also Brent Yorgey, /Monoids: Theme and Variations/, published in the 2012 Haskell Symposium: <http://www.cis.upenn.edu/~byorgey/pub/monoid-pearl.pdf>; video: <http://www.youtube.com/watch?v=X-8NCkD2vOw>.
+--   <http://byorgey.wordpress.com/2009/10/28/collecting-attributes/#comment-2030>.  See also Brent Yorgey, /Monoids: Theme and Variations/, published in the 2012 Haskell Symposium: <http://ozark.hendrix.edu/~yorgey/pub/monoid-pearl.pdf>; video: <http://www.youtube.com/watch?v=X-8NCkD2vOw>.
 newtype Envelope v n = Envelope (Option (v n -> Max n))
 
 instance Wrapped (Envelope v n) where
@@ -116,16 +116,24 @@
 
 instance Rewrapped (Envelope v n) (Envelope v' n')
 
+-- | \"Apply\" an envelope by turning it into a function.  @Nothing@
+--   is returned iff the envelope is empty.
 appEnvelope :: Envelope v n -> Maybe (v n -> n)
 appEnvelope (Envelope (Option e)) = (getMax .) <$> e
 
+-- | A convenient way to transform an envelope, by specifying a
+--   transformation on the underlying @v n -> n@ function.  The empty
+--   envelope is unaffected.
 onEnvelope :: ((v n -> n) -> v n -> n) -> Envelope v n -> Envelope v n
 onEnvelope t = over (_Wrapping' Envelope . mapped) ((Max .) . t . (getMax .))
 
+-- | Create an envelope from a @v n -> n@ function.
 mkEnvelope :: (v n -> n) -> Envelope v n
 mkEnvelope = Envelope . Option . Just . (Max .)
 
--- | Create an envelope for the given point.
+-- | Create a point envelope for the given point.  A point envelope
+--   has distance zero to a bounding hyperplane in every direction.
+--   Note this is /not/ the same as the empty envelope.
 pointEnvelope :: (Fractional n, Metric v) => Point v n -> Envelope v n
 pointEnvelope p = moveTo p (mkEnvelope $ const 0)
 
@@ -217,8 +225,8 @@
 
 However, it turns out that if v and w are perpendicular, then t^-1 v
 will be perpendicular to t^T w, that is, the *transpose* of t (when
-considered as a matrix) applied to w.  The proof is simple: if vand w
-are perpendicular then v . w = v^T w = 0.  Thus,
+considered as a matrix) applied to w.  The proof is simple. Recall
+that v and w are perpendicular if and only if v . w = v^T w = 0.  Thus,
 
   (t^-1 v) . (t^T w) = (t^-1 v)^T (t^T w) = v^T t^-T t^T w = v^T w = 0.
 
@@ -350,6 +358,7 @@
 extent :: (V a ~ v, N a ~ n, Enveloped a) => v n -> a -> Maybe (n, n)
 extent v a = (\f -> (-f (negated v), f v)) <$> (appEnvelope . getEnvelope $ a)
 
--- | The smallest positive vector that bounds the envelope of an object.
+-- | The smallest positive /axis-parallel/ vector that bounds the
+--   envelope of an object.
 size :: (V a ~ v, N a ~ n, Enveloped a, HasBasis v) => a -> v n
 size d = tabulate $ \(E l) -> diameter (zero & l .~ 1) d
diff --git a/src/Diagrams/Core/Measure.hs b/src/Diagrams/Core/Measure.hs
--- a/src/Diagrams/Core/Measure.hs
+++ b/src/Diagrams/Core/Measure.hs
@@ -56,7 +56,8 @@
 local :: Num n => n -> Measure n
 local x = views _1 (*x)
 
--- | Global units are ?
+-- | Global units are scaled so that they are interpreted relative to
+--   the size of the final rendered diagram.
 global :: Num n => n -> Measure n
 global x = views _2 (*x)
 
diff --git a/src/Diagrams/Core/Points.hs b/src/Diagrams/Core/Points.hs
--- a/src/Diagrams/Core/Points.hs
+++ b/src/Diagrams/Core/Points.hs
@@ -30,6 +30,7 @@
 type instance V (Point v n) = v
 type instance N (Point v n) = n
 
+-- | Reflect a point across the origin.
 mirror :: (Additive v, Num n) => Point v n -> Point v n
 mirror = reflectThrough origin