diff --git a/Control/Monad/Trans/Resource.hs b/Control/Monad/Trans/Resource.hs
--- a/Control/Monad/Trans/Resource.hs
+++ b/Control/Monad/Trans/Resource.hs
@@ -27,6 +27,7 @@
     , resourceForkIO
       -- * Monad transformation
     , transResourceT
+    , joinResourceT
       -- * A specific Exception transformer
     , ExceptionT (..)
     , runExceptionT_
@@ -48,6 +49,12 @@
     , InvalidAccess (..)
       -- * Re-exports
     , MonadBaseControl
+      -- * Internal state
+      -- $internalState
+    , InternalState
+    , getInternalState
+    , runInternalState
+    , withInternalState
     ) where
 
 import Data.Typeable
@@ -384,6 +391,14 @@
                -> ResourceT n b
 transResourceT f (ResourceT mx) = ResourceT (\r -> f (mx r))
 
+-- | This function mirrors @join@ at the transformer level: it will collapse
+-- two levels of @ResourceT@ into a single @ResourceT@.
+--
+-- Since 0.4.6
+joinResourceT :: ResourceT (ResourceT m) a
+              -> ResourceT m a
+joinResourceT (ResourceT f) = ResourceT $ \r -> unResourceT (f r) r
+
 -------- All of our monad et al instances
 instance Functor m => Functor (ResourceT m) where
     fmap f (ResourceT m) = ResourceT $ \r -> fmap f (m r)
@@ -424,7 +439,10 @@
      restoreM (StMT base) = ResourceT $ const $ restoreM base
 instance Monad m => MonadThrow (ExceptionT m) where
     monadThrow = ExceptionT . return . Left . E.toException
-
+instance MonadResource m => MonadResource (ExceptionT m) where
+    liftResourceT = lift . liftResourceT
+instance MonadIO m => MonadIO (ExceptionT m) where
+    liftIO = lift . liftIO
 
 -- | The express purpose of this transformer is to allow non-@IO@-based monad
 -- stacks to catch exceptions via the 'MonadThrow' typeclass.
@@ -668,3 +686,35 @@
 class (MonadBaseControl IO m, MonadThrow m, MonadUnsafeIO m, MonadIO m, Applicative m) => MonadResourceBase m
 instance (MonadBaseControl IO m, MonadThrow m, MonadUnsafeIO m, MonadIO m, Applicative m) => MonadResourceBase m
 #endif
+
+-- $internalState
+--
+-- A @ResourceT@ internally is a modified @ReaderT@ monad transformer holding
+-- onto a mutable reference to all of the release actions still remaining to be
+-- performed. If you are building up a custom application monad, it may be more
+-- efficient to embed this @ReaderT@ functionality directly in your own monad
+-- instead of wrapping around @ResourceT@ itself. This section provides you the
+-- means of doing so.
+
+-- | Get the internal state of the current @ResourceT@.
+--
+-- Since 0.4.6
+getInternalState :: Monad m => ResourceT m InternalState
+getInternalState = ResourceT return
+
+-- | The internal state held by a @ResourceT@ transformer.
+--
+-- Since 0.4.6
+type InternalState = I.IORef ReleaseMap
+
+-- | Unwrap a @ResourceT@ using the given @InternalState@.
+--
+-- Since 0.4.6
+runInternalState :: ResourceT m a -> InternalState -> m a
+runInternalState = unResourceT
+
+-- | Run an action in the underlying monad, providing it the @InternalState.
+--
+-- Since 0.4.6
+withInternalState :: (InternalState -> m a) -> ResourceT m a
+withInternalState = ResourceT
diff --git a/resourcet.cabal b/resourcet.cabal
--- a/resourcet.cabal
+++ b/resourcet.cabal
@@ -1,5 +1,5 @@
 Name:                resourcet
-Version:             0.4.5
+Version:             0.4.6
 Synopsis:            Deterministic allocation and freeing of scarce resources.
 Description:
 	This package was originally included with the conduit package, and has since been split off. For more information, please see <http://www.yesodweb.com/book/conduits>.