diff --git a/Control/Monad/Conc/Class.hs b/Control/Monad/Conc/Class.hs
--- a/Control/Monad/Conc/Class.hs
+++ b/Control/Monad/Conc/Class.hs
@@ -70,7 +70,6 @@
 import Control.Monad.STM.Class (MonadSTM, TVar, readTVar)
 import Control.Monad.Trans.Control (MonadTransControl, StT, liftWith)
 import Data.Proxy (Proxy(..))
-import Data.Typeable (Typeable)
 
 -- for the 'IO' instance
 import qualified Control.Concurrent as IO
@@ -115,6 +114,7 @@
       , putMVar
       , tryPutMVar
       , readMVar
+      , tryReadMVar
       , takeMVar
       , tryTakeMVar
       , (newCRef | newCRefN)
@@ -252,10 +252,16 @@
   tryPutMVar :: MVar m a -> a -> m Bool
 
   -- | Block until a value is present in the @MVar@, and then return
-  -- it. As with 'readMVar', this does not \"remove\" the value,
-  -- multiple reads are possible.
+  -- it. This does not \"remove\" the value, multiple reads are
+  -- possible.
   readMVar :: MVar m a -> m a
 
+  -- | Attempt to read a value from a @MVar@ non-blockingly, returning
+  -- a 'Just' (and emptying the @MVar@) if there is something there,
+  -- otherwise returning 'Nothing'. As with 'readMVar', this does not
+  -- \"remove\" the value.
+  tryReadMVar :: MVar m a -> m (Maybe a)
+
   -- | Take a value from a @MVar@. This \"empties\" the @MVar@,
   -- allowing a new value to be put in. This will block if there is no
   -- value in the @MVar@ already, until one has been put.
@@ -346,14 +352,6 @@
   -- had raised it with 'throw'. This can interrupt a blocked action.
   throwTo :: Exception e => ThreadId m -> e -> m ()
 
-  -- | Does nothing.
-  --
-  -- During testing, records a message which shows up in the trace.
-  --
-  -- > _concMessage _ = pure ()
-  _concMessage :: Typeable a => a -> m ()
-  _concMessage _ = pure ()
-
 -------------------------------------------------------------------------------
 -- Utilities
 
@@ -510,6 +508,7 @@
   getNumCapabilities = IO.getNumCapabilities
   setNumCapabilities = IO.setNumCapabilities
   readMVar           = IO.readMVar
+  tryReadMVar        = IO.tryReadMVar
   myThreadId         = IO.myThreadId
   yield              = IO.yield
   threadDelay        = IO.threadDelay
@@ -535,7 +534,7 @@
 -- Transformer instances
 
 #define INSTANCE(T,C,F)                                          \
-instance C => MonadConc (T m) where                             { \
+instance C => MonadConc (T m) where                            { \
   type STM      (T m) = STM m                                  ; \
   type MVar     (T m) = MVar m                                 ; \
   type CRef     (T m) = CRef m                                 ; \
@@ -559,6 +558,7 @@
   newEmptyMVar       = lift newEmptyMVar                       ; \
   newEmptyMVarN      = lift . newEmptyMVarN                    ; \
   readMVar           = lift . readMVar                         ; \
+  tryReadMVar        = lift . tryReadMVar                      ; \
   putMVar v          = lift . putMVar v                        ; \
   tryPutMVar v       = lift . tryPutMVar v                     ; \
   takeMVar           = lift . takeMVar                         ; \
@@ -574,9 +574,7 @@
   casCRef r t        = lift . casCRef r t                      ; \
   modifyCRefCAS r    = lift . modifyCRefCAS r                  ; \
   atomically         = lift . atomically                       ; \
-  readTVarConc       = lift . readTVarConc                     ; \
-                                                                 \
-  _concMessage    = lift . _concMessage                        }
+  readTVarConc       = lift . readTVarConc                     }
 
 -- | New threads inherit the reader state of their parent, but do not
 -- communicate results back.
diff --git a/concurrency.cabal b/concurrency.cabal
--- a/concurrency.cabal
+++ b/concurrency.cabal
@@ -2,7 +2,7 @@
 -- documentation, see http://haskell.org/cabal/users-guide/
 
 name:                concurrency
-version:             1.0.0.0
+version:             1.1.0.0
 synopsis:            Typeclasses, functions, and data types for concurrency and STM.
 
 description:
@@ -38,7 +38,7 @@
   This used to be part of dejafu, but with the dejafu-0.4.0.0 release,
   it was split out into its own package.
   .
-  == Why and not something else?
+  == Why this and not something else?
   .
   * Why not base: like lifted-base, concurrency uses typeclasses to
     make function types more generic. This automatically eliminates
@@ -78,7 +78,7 @@
 source-repository this
   type:     git
   location: https://github.com/barrucadu/dejafu.git
-  tag:      concurrency-0.1.0.0
+  tag:      concurrency-1.1.0.0
 
 library
   exposed-modules:     Control.Monad.Conc.Class