diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,10 @@
+## Version 0.5.3 (2018-03-12)
+
+- Add `Semigroup` and `Monoid` instances for `GenT` that lift the inner `Monoid` ([#156][156], [@andrewthad][andrewthad])
+- `Gen.unicode` no longer generates non-characters ([#154][154], [@johnchandlerburnham][johnchandlerburnham])
+- Documentation improvements ([#162][162], [@fisx][fisx])
+- Documentation fixes ([#157][157], [@dredozubov][dredozubov])
+
 ## Version 0.5.2 (2018-02-05)
 
 - Add doc explaining use of `withTests 1` ([#134][134], [@chris-martin][chris-martin])
@@ -78,7 +85,23 @@
   https://github.com/gwils
 [LightAndLight]:
   https://github.com/LightAndLight
+[johnchandlerburnham]:
+  https://github.com/johnchandlerburnham
+[andrewthad]:
+  https://github.com/andrewthad
+[dredozubov]:
+  https://github.com/dredozubov
+[fisx]:
+  https://github.com/fisx
 
+[162]:
+  https://github.com/hedgehogqa/haskell-hedgehog/pull/162
+[157]:
+  https://github.com/hedgehogqa/haskell-hedgehog/pull/157
+[156]:
+  https://github.com/hedgehogqa/haskell-hedgehog/pull/156
+[154]:
+  https://github.com/hedgehogqa/haskell-hedgehog/pull/154
 [150]:
   https://github.com/hedgehogqa/haskell-hedgehog/pull/150
 [142]:
diff --git a/LICENSE b/LICENSE
--- a/LICENSE
+++ b/LICENSE
@@ -1,4 +1,4 @@
-Copyright 2017, Jacob Stanley
+Copyright 2017-2018, Jacob Stanley
 All Rights Reserved.
 
 Redistribution and use in source and binary forms, with or without
diff --git a/hedgehog.cabal b/hedgehog.cabal
--- a/hedgehog.cabal
+++ b/hedgehog.cabal
@@ -1,4 +1,4 @@
-version: 0.5.2
+version: 0.5.3
 
 name:
   hedgehog
@@ -49,13 +49,13 @@
   build-depends:
       base                            >= 3          && < 5
     , ansi-terminal                   >= 0.6        && < 0.9
-    , async                           >= 2.0        && < 2.2
+    , async                           >= 2.0        && < 2.3
     , bytestring                      >= 0.10       && < 0.11
     , concurrent-output               >= 1.7        && < 1.11
     , containers                      >= 0.4        && < 0.6
     , directory                       >= 1.2        && < 1.4
-    , exceptions                      >= 0.7        && < 0.9
-    , lifted-async                    >= 0.7        && < 0.10
+    , exceptions                      >= 0.7        && < 0.11
+    , lifted-async                    >= 0.7        && < 0.11
     , mmorph                          >= 1.0        && < 1.2
     , monad-control                   >= 1.0        && < 1.1
     , mtl                             >= 2.1        && < 2.3
diff --git a/src/Hedgehog.hs b/src/Hedgehog.hs
--- a/src/Hedgehog.hs
+++ b/src/Hedgehog.hs
@@ -98,6 +98,7 @@
   , failure
   , assert
   , (===)
+  , (/==)
   , tripping
 
   , eval
@@ -146,7 +147,7 @@
 import           Hedgehog.Internal.HTraversable (HTraversable(..))
 import           Hedgehog.Internal.Opaque (Opaque(..))
 import           Hedgehog.Internal.Property (annotate, annotateShow)
-import           Hedgehog.Internal.Property (assert, (===))
+import           Hedgehog.Internal.Property (assert, (===), (/==))
 import           Hedgehog.Internal.Property (discard, failure, success)
 import           Hedgehog.Internal.Property (DiscardLimit, withDiscards)
 import           Hedgehog.Internal.Property (eval, evalM, evalIO)
diff --git a/src/Hedgehog/Internal/Gen.hs b/src/Hedgehog/Internal/Gen.hs
--- a/src/Hedgehog/Internal/Gen.hs
+++ b/src/Hedgehog/Internal/Gen.hs
@@ -142,6 +142,7 @@
 
   -- ** Characters
   , isSurrogate
+  , isNoncharacter
 
   -- ** Subterms
   , Vec(..)
@@ -152,7 +153,7 @@
   , renderNodes
   ) where
 
-import           Control.Applicative (Alternative(..))
+import           Control.Applicative (Alternative(..),liftA2)
 import           Control.Monad (MonadPlus(..), filterM, replicateM, ap, join)
 import           Control.Monad.Base (MonadBase(..))
 import           Control.Monad.Catch (MonadThrow(..), MonadCatch(..))
@@ -189,6 +190,8 @@
 import           Data.Map (Map)
 import qualified Data.Map as Map
 import qualified Data.Maybe as Maybe
+import           Data.Semigroup (Semigroup)
+import qualified Data.Semigroup as Semigroup
 import           Data.Sequence (Seq)
 import qualified Data.Sequence as Seq
 import           Data.Set (Set)
@@ -521,6 +524,13 @@
 ------------------------------------------------------------------------
 -- GenT instances
 
+instance (Monad m, Semigroup a) => Semigroup (GenT m a) where
+  (<>) = liftA2 (Semigroup.<>)
+
+instance (Monad m, Monoid a) => Monoid (GenT m a) where
+  mappend = liftA2 mappend
+  mempty = return mempty
+
 instance Functor m => Functor (GenT m) where
   fmap f gen =
     GenT $ \seed size ->
@@ -1036,14 +1046,14 @@
 latin1 =
   enum '\0' '\255'
 
--- | Generates a Unicode character, excluding invalid standalone surrogates:
+-- | Generates a Unicode character, excluding noncharacters and invalid standalone surrogates:
 --   @'\0'..'\1114111' (excluding '\55296'..'\57343')@
 --
 unicode :: MonadGen m => m Char
 unicode =
-  filter (not . isSurrogate) unicodeAll
+  filter (not . isNoncharacter) $ filter (not . isSurrogate) unicodeAll
 
--- | Generates a Unicode character, including invalid standalone surrogates:
+-- | Generates a Unicode character, including noncharacters and invalid standalone surrogates:
 --   @'\0'..'\1114111'@
 --
 unicodeAll :: MonadGen m => m Char
@@ -1055,6 +1065,12 @@
 isSurrogate :: Char -> Bool
 isSurrogate x =
   x >= '\55296' && x <= '\57343'
+
+-- | Check if a character is one of the noncharacters '\65534', '\65535'.
+--
+isNoncharacter :: Char -> Bool
+isNoncharacter x =
+  x == '\65534' || x == '\65535'
 
 ------------------------------------------------------------------------
 -- Combinators - Strings
diff --git a/src/Hedgehog/Internal/HTraversable.hs b/src/Hedgehog/Internal/HTraversable.hs
--- a/src/Hedgehog/Internal/HTraversable.hs
+++ b/src/Hedgehog/Internal/HTraversable.hs
@@ -7,5 +7,7 @@
 
 -- | Higher-order traversable functors.
 --
+-- This is used internally to make symbolic variables concrete given an 'Environment'.
+--
 class HTraversable t where
   htraverse :: Applicative f => (forall a. g a -> f (h a)) -> t g -> f (t h)
diff --git a/src/Hedgehog/Internal/Property.hs b/src/Hedgehog/Internal/Property.hs
--- a/src/Hedgehog/Internal/Property.hs
+++ b/src/Hedgehog/Internal/Property.hs
@@ -55,6 +55,7 @@
   , success
   , assert
   , (===)
+  , (/==)
 
   , eval
   , evalM
@@ -552,6 +553,22 @@
   else
     withFrozenCallStack $ failDiff x y
 
+infix 4 /==
+
+-- | Fails the test if the two arguments provided are equal.
+--
+(/==) :: (MonadTest m, Eq a, Show a, HasCallStack) => a -> a -> m ()
+(/==) x y = do
+  ok <- withFrozenCallStack $ eval (x /= y)
+  if ok then
+    success
+  else
+    withFrozenCallStack $
+      failWith Nothing $ unlines [
+          "━━━ Both equal to ━━━"
+        , showPretty x
+        ]
+
 -- | Fails the test if the value throws an exception when evaluated to weak
 --   head normal form (WHNF).
 --
@@ -728,7 +745,7 @@
 mapConfig f (Property cfg t) =
   Property (f cfg) t
 
--- | Set the number times a property should be executed before it is considered
+-- | Set the number of times a property should be executed before it is considered
 --   successful.
 --
 --   If you have a test that does not involve any generators and thus does not
@@ -739,21 +756,21 @@
 withTests n =
   mapConfig $ \config -> config { propertyTestLimit = n }
 
--- | Set the number times a property is allowed to discard before the test
+-- | Set the number of times a property is allowed to discard before the test
 --   runner gives up.
 --
 withDiscards :: DiscardLimit -> Property -> Property
 withDiscards n =
   mapConfig $ \config -> config { propertyDiscardLimit = n }
 
--- | Set the number times a property is allowed to shrink before the test
+-- | Set the number of times a property is allowed to shrink before the test
 --   runner gives up and prints the counterexample.
 --
 withShrinks :: ShrinkLimit -> Property -> Property
 withShrinks n =
   mapConfig $ \config -> config { propertyShrinkLimit = n }
 
--- | Set the number times a property will be executed for each shrink before
+-- | Set the number of times a property will be executed for each shrink before
 --   the test runner gives up and tries a different shrink. See 'ShrinkRetries'
 --   for more information.
 --
diff --git a/src/Hedgehog/Internal/Range.hs b/src/Hedgehog/Internal/Range.hs
--- a/src/Hedgehog/Internal/Range.hs
+++ b/src/Hedgehog/Internal/Range.hs
@@ -72,6 +72,10 @@
 -- | A range describes the bounds of a number to generate, which may or may not
 --   be dependent on a 'Size'.
 --
+--   The constructor takes an origin between the lower and upper bound, and a
+--   function from 'Size' to bounds.  As the size goes towards @0@, the values
+--   go towards the origin.
+--
 data Range a =
   Range !a (Size -> (a, a))
 
@@ -164,7 +168,11 @@
 --   >>> origin $ constantFrom 2000 1970 2100
 --   2000
 --
-constantFrom :: a -> a -> a -> Range a
+constantFrom ::
+     a -- ^ Origin (the value produced when the size parameter is 0).
+  -> a -- ^ Lower bound (the bottom of the range when the size parameter is 99).
+  -> a -- ^ Upper bound (the top of the range when the size parameter is 99).
+  -> Range a
 constantFrom z x y =
   Range z $ \_ -> (x, y)
 
@@ -210,7 +218,11 @@
 --   >>> bounds 99 $ linearFrom 0 (-10) 20
 --   (-10,20)
 --
-linearFrom :: Integral a => a -> a -> a -> Range a
+linearFrom :: Integral a
+  => a -- ^ Origin (the value produced when the size parameter is 0).
+  -> a -- ^ Lower bound (the bottom of the range when the size parameter is 99).
+  -> a -- ^ Upper bound (the top of the range when the size parameter is 99).
+  -> Range a
 linearFrom z x y =
   Range z $ \sz ->
     let
@@ -353,7 +365,11 @@
 --   >>> bounds 99 $ exponentialFrom x (-128) 512
 --   (-128,512)
 --
-exponentialFrom :: Integral a => a -> a -> a -> Range a
+exponentialFrom :: Integral a
+  => a -- ^ Origin (the value produced when the size parameter is 0).
+  -> a -- ^ Lower bound (the bottom of the range when the size parameter is 99).
+  -> a -- ^ Upper bound (the top of the range when the size parameter is 99).
+  -> Range a
 exponentialFrom z x y =
   Range z $ \sz ->
     let