diff --git a/Control/Monad/Sharing.hs b/Control/Monad/Sharing.hs
--- a/Control/Monad/Sharing.hs
+++ b/Control/Monad/Sharing.hs
@@ -84,6 +84,26 @@
  where
   trans _ = return
 
+instance Monad m => Trans m [Bool] [Bool]
+ where
+  trans _ = return
+
+instance Monad m => Trans m [Int] [Int]
+ where
+  trans _ = return
+
+instance Monad m => Trans m [Char] [Char]
+ where
+  trans _ = return
+
+instance Monad m => Trans m [Float] [Float]
+ where
+  trans _ = return
+
+instance Monad m => Trans m [Double] [Double]
+ where
+  trans _ = return
+
 -- | An instance for lists with monadic elements.
 instance (Monad m, Trans m a a) => Trans m [m a] [m a]
  where
@@ -133,3 +153,8 @@
  where
   trans _ Nil         = return []
   trans f (Cons x xs) = return (:) `ap` join (f x) `ap` join (f xs)
+
+instance (Monad m, Trans m a b) => Trans m [a] (List m b)
+ where
+  trans _ []     = return Nil
+  trans f (x:xs) = return Cons `ap` f (return x) `ap` f (return xs)
diff --git a/Control/Monad/Sharing/Lazy.hs b/Control/Monad/Sharing/Lazy.hs
--- a/Control/Monad/Sharing/Lazy.hs
+++ b/Control/Monad/Sharing/Lazy.hs
@@ -25,6 +25,7 @@
 
  ) where
 
+import Control.Monad.Trans
 import Control.Monad.Sharing
 
 -- For fast and easy implementation of typed stores..
@@ -71,6 +72,16 @@
   mzero       = Lazy (\_ _ -> mzero)
   a `mplus` b = Lazy (\c s -> fromLazy a c s `mplus` fromLazy b c s)
 
+-- @Lazy@ is a monad transformer.
+instance MonadTrans Lazy
+ where
+  lift a = Lazy (\c s -> a >>= \x -> c x s)
+
+-- If the underlying monad supports IO we can lift this functionality.
+instance MonadIO m => MonadIO (Lazy m)
+ where
+  liftIO = lift . liftIO
+
 -- The @Sharing@ instance memoizes nested monadic values recursively.
 instance Monad m => Sharing (Lazy m)
  where
@@ -108,4 +119,3 @@
 
 typed :: Untyped -> a
 typed (Untyped x) = unsafeCoerce x
-
diff --git a/Setup.hs b/Setup.hs
--- a/Setup.hs
+++ b/Setup.hs
@@ -5,6 +5,7 @@
 main = defaultMainWithHooks $ simpleUserHooks { runTests = runTestSuite }
 
 runTestSuite _ _ _ _ =
- do pid <- runCommand "ghc -hide-package monads-fd -e main Test.hs"
+ do pid <- runCommand $ "ghc -hide-package monads-fd "
+                     ++ "-hide-package transformers -e main Test.hs"
     waitForProcess pid >>= exitWith
 
diff --git a/explicit-sharing.cabal b/explicit-sharing.cabal
--- a/explicit-sharing.cabal
+++ b/explicit-sharing.cabal
@@ -1,5 +1,5 @@
 Name:          explicit-sharing
-Version:       0.3.1.2
+Version:       0.3.1.3
 Cabal-Version: >= 1.6
 Synopsis:      Explicit Sharing of Monadic Effects
 Description: