diff --git a/deferred-folds.cabal b/deferred-folds.cabal
--- a/deferred-folds.cabal
+++ b/deferred-folds.cabal
@@ -1,7 +1,7 @@
 name:
   deferred-folds
 version:
-  0.6.10
+  0.6.11
 category:
   Folding
 synopsis:
diff --git a/library/DeferredFolds/Unfold.hs b/library/DeferredFolds/Unfold.hs
--- a/library/DeferredFolds/Unfold.hs
+++ b/library/DeferredFolds/Unfold.hs
@@ -1,7 +1,7 @@
 module DeferredFolds.Unfold
 where
 
-import DeferredFolds.Prelude
+import DeferredFolds.Prelude hiding (fold)
 import qualified DeferredFolds.Prelude as A
 import qualified DeferredFolds.UnfoldM as B
 import qualified Data.Map.Strict as C
@@ -125,11 +125,17 @@
 unfoldM :: B.UnfoldM Identity input -> Unfold input
 unfoldM (B.UnfoldM runFoldM) = Unfold (\ step init -> runIdentity (runFoldM (\ a b -> return (step a b)) init))
 
+{-| Lift a fold input mapping function into a mapping of unfolds -}
+{-# INLINE mapFoldInput #-}
+mapFoldInput :: (forall x. Fold b x -> Fold a x) -> Unfold a -> Unfold b
+mapFoldInput newFold unfold = Unfold $ \ step init -> fold (newFold (Fold step init id)) unfold
+
 {-| Construct from any foldable -}
 {-# INLINE foldable #-}
 foldable :: Foldable foldable => foldable a -> Unfold a
 foldable foldable = Unfold (\ step init -> A.foldl' step init foldable)
 
+{-| Filter the values given a predicate -}
 {-# INLINE filter #-}
 filter :: (a -> Bool) -> Unfold a -> Unfold a
 filter test (Unfold run) = Unfold (\ step -> run (\ state element -> if test element then step state element else state))
diff --git a/library/DeferredFolds/UnfoldM.hs b/library/DeferredFolds/UnfoldM.hs
--- a/library/DeferredFolds/UnfoldM.hs
+++ b/library/DeferredFolds/UnfoldM.hs
@@ -1,7 +1,7 @@
 module DeferredFolds.UnfoldM
 where
 
-import DeferredFolds.Prelude hiding (mapM_)
+import DeferredFolds.Prelude hiding (mapM_, foldM)
 import qualified DeferredFolds.Prelude as A
 import qualified Data.ByteString.Internal as ByteString
 import qualified Data.ByteString.Short.Internal as ShortByteString
@@ -105,6 +105,11 @@
     finalState <- foldlM' step initialState view
     extract finalState
 
+{-| Lift a fold input mapping function into a mapping of unfolds -}
+{-# INLINE mapFoldMInput #-}
+mapFoldMInput :: Monad m => (forall x. FoldM m b x -> FoldM m a x) -> UnfoldM m a -> UnfoldM m b
+mapFoldMInput newFoldM unfoldM = UnfoldM $ \ step init -> foldM (newFoldM (FoldM step (return init) return)) unfoldM
+
 {-| Construct from any foldable -}
 {-# INLINE foldable #-}
 foldable :: (Monad m, Foldable foldable) => foldable a -> UnfoldM m a
@@ -120,7 +125,7 @@
 foldrRunner :: Monad m => (forall x. (a -> x -> x) -> x -> x) -> UnfoldM m a
 foldrRunner run = UnfoldM (\ stepM -> run (\ x k z -> stepM z x >>= k) return)
 
-{-| Filter -}
+{-| Filter the values given a predicate -}
 {-# INLINE filter #-}
 filter :: Monad m => (a -> m Bool) -> UnfoldM m a -> UnfoldM m a
 filter test (UnfoldM run) = UnfoldM (\ step -> run (\ state element -> test element >>= bool (return state) (step state element)))