diff --git a/library/STMContainers/Bimap.hs b/library/STMContainers/Bimap.hs
--- a/library/STMContainers/Bimap.hs
+++ b/library/STMContainers/Bimap.hs
@@ -3,6 +3,7 @@
   Bimap,
   Association,
   new,
+  newIO,
   insert1,
   insert2,
   delete1,
@@ -25,7 +26,7 @@
 -- A bidirectional map.
 -- Essentially a bijection between subsets of its two argument types.
 -- 
--- For one value of a left-hand type there this map contains one value 
+-- For one value of a left-hand type this map contains one value 
 -- of the right-hand type and vice versa.
 data Bimap a b = 
   Bimap {m1 :: !(Map.Map a b), m2 :: !(Map.Map b a)}
@@ -39,6 +40,15 @@
 {-# INLINABLE new #-}
 new :: STM (Bimap a b)
 new = Bimap <$> Map.new <*> Map.new
+
+-- |
+-- Construct a new bimap in IO.
+-- 
+-- This is useful for creating it on a top-level using 'unsafePerformIO', 
+-- because using 'atomically' inside 'unsafePerformIO' isn't possible.
+{-# INLINABLE newIO #-}
+newIO :: IO (Bimap a b)
+newIO = Bimap <$> Map.newIO <*> Map.newIO
 
 -- |
 -- Check on being empty.
diff --git a/library/STMContainers/HAMT.hs b/library/STMContainers/HAMT.hs
--- a/library/STMContainers/HAMT.hs
+++ b/library/STMContainers/HAMT.hs
@@ -25,6 +25,10 @@
 new :: STM (HAMT e)
 new = Nodes.new
 
+{-# INLINE newIO #-}
+newIO :: IO (HAMT e)
+newIO = Nodes.newIO
+
 {-# INLINE null #-}
 null :: HAMT e -> STM Bool
 null = Nodes.null
diff --git a/library/STMContainers/HAMT/Nodes.hs b/library/STMContainers/HAMT/Nodes.hs
--- a/library/STMContainers/HAMT/Nodes.hs
+++ b/library/STMContainers/HAMT/Nodes.hs
@@ -25,6 +25,10 @@
 new :: STM (Nodes e)
 new = newTVar WordArray.empty
 
+{-# INLINE newIO #-}
+newIO :: IO (Nodes e)
+newIO = newTVarIO WordArray.empty
+
 insert :: (Element e) => e -> Hash -> ElementKey e -> Level.Level -> Nodes e -> STM ()
 insert e h k l ns = do
   a <- readTVar ns
diff --git a/library/STMContainers/Map.hs b/library/STMContainers/Map.hs
--- a/library/STMContainers/Map.hs
+++ b/library/STMContainers/Map.hs
@@ -3,6 +3,7 @@
   Map,
   Key,
   new,
+  newIO,
   insert,
   delete,
   lookup,
@@ -80,6 +81,15 @@
 {-# INLINE new #-}
 new :: STM (Map k v)
 new = Map <$> HAMT.new
+
+-- |
+-- Construct a new map in IO.
+-- 
+-- This is useful for creating it on a top-level using 'unsafePerformIO', 
+-- because using 'atomically' inside 'unsafePerformIO' isn't possible.
+{-# INLINE newIO #-}
+newIO :: IO (Map k v)
+newIO = Map <$> HAMT.newIO
 
 -- |
 -- Check, whether the map is empty.
diff --git a/library/STMContainers/Multimap.hs b/library/STMContainers/Multimap.hs
--- a/library/STMContainers/Multimap.hs
+++ b/library/STMContainers/Multimap.hs
@@ -3,6 +3,7 @@
   Multimap,
   Association,
   new,
+  newIO,
   insert,
   delete,
   lookup,
@@ -79,7 +80,7 @@
 -- 
 -- The strategy is over a unit since we already know,
 -- which value we're focusing on and it doesn't make sense to replace it,
--- however we still can still decide wether to keep or remove it.
+-- however we still can decide wether to keep or remove it.
 {-# INLINE focus #-}
 focus :: (Association k v) => Focus.StrategyM STM () r -> v -> k -> Multimap k v -> STM r
 focus = 
@@ -123,6 +124,15 @@
 {-# INLINE new #-}
 new :: STM (Multimap k v)
 new = Multimap <$> Map.new
+
+-- |
+-- Construct a new multimap in IO.
+-- 
+-- This is useful for creating it on a top-level using 'unsafePerformIO', 
+-- because using 'atomically' inside 'unsafePerformIO' isn't possible.
+{-# INLINE newIO #-}
+newIO :: IO (Multimap k v)
+newIO = Multimap <$> Map.newIO
 
 -- |
 -- Check on being empty.
diff --git a/library/STMContainers/Set.hs b/library/STMContainers/Set.hs
--- a/library/STMContainers/Set.hs
+++ b/library/STMContainers/Set.hs
@@ -3,6 +3,7 @@
   Set,
   Element,
   new,
+  newIO,
   insert,
   delete,
   lookup,
@@ -61,7 +62,7 @@
 -- 
 -- The strategy is over a unit since we already know, 
 -- which element we're focusing on and it doesn't make sense to replace it,
--- however we still can still decide wether to keep or remove it.
+-- however we still can decide wether to keep or remove it.
 {-# INLINE focus #-}
 focus :: (Element e) => Focus.StrategyM STM () r -> e -> Set e -> STM r
 focus s e = HAMT.focus elementStrategy e . hamt
@@ -80,6 +81,15 @@
 {-# INLINE new #-}
 new :: STM (Set e)
 new = Set <$> HAMT.new
+
+-- |
+-- Construct a new set in IO.
+-- 
+-- This is useful for creating it on a top-level using 'unsafePerformIO', 
+-- because using 'atomically' inside 'unsafePerformIO' isn't possible.
+{-# INLINE newIO #-}
+newIO :: IO (Set e)
+newIO = Set <$> HAMT.newIO
 
 -- |
 -- Check, whether the set is empty.
diff --git a/stm-containers.cabal b/stm-containers.cabal
--- a/stm-containers.cabal
+++ b/stm-containers.cabal
@@ -1,15 +1,19 @@
 name:
   stm-containers
 version:
-  0.1.3
+  0.1.4
 synopsis:
   Containers for STM
 description:
-  This library is based on an STM-specialized implementation of
+  This library is based on an STM-specialized implementation of a
   Hash Array Mapped Trie.
-  It provides very efficient implementations of @Map@ and @Set@ data structures,
+  It provides efficient implementations of @Map@, @Set@ 
+  and other data structures,
   which are slightly slower than their counterparts from \"unordered-containers\",
   but scale very well on concurrent access patterns.
+  .
+  For details on performance of the library see
+  <http://nikita-volkov.github.io/stm-containers/ this blog post>.
 category:
   Data Structures, STM, Concurrency
 homepage:
@@ -60,14 +64,12 @@
     hashable < 1.3,
     -- control:
     focus > 0.1.0 && < 0.2,
-    -- preludes:
-    base-prelude == 0.1.*,
     -- debugging:
     loch-th == 0.2.*,
     placeholders == 0.1.*,
     -- general:
     primitive == 0.5.*,
-    base >= 4.5 && < 4.8
+    base-prelude == 0.1.*
   default-extensions:
     Arrows, BangPatterns, ConstraintKinds, DataKinds, DefaultSignatures, DeriveDataTypeable, DeriveFunctor, DeriveGeneric, EmptyDataDecls, FlexibleContexts, FlexibleInstances, FunctionalDependencies, GADTs, GeneralizedNewtypeDeriving, ImpredicativeTypes, LambdaCase, LiberalTypeSynonyms, MagicHash, MultiParamTypeClasses, MultiWayIf, NoImplicitPrelude, NoMonomorphismRestriction, OverloadedStrings, PatternGuards, ParallelListComp, QuasiQuotes, RankNTypes, RecordWildCards, ScopedTypeVariables, StandaloneDeriving, TemplateHaskell, TupleSections, TypeFamilies, TypeOperators, UnboxedTuples
   default-language:
@@ -92,14 +94,12 @@
     hashable < 1.3,
     -- control:
     focus > 0.1.0 && < 0.2,
-    -- preludes:
-    base-prelude == 0.1.*,
     -- debugging:
     loch-th == 0.2.*,
     placeholders == 0.1.*,
     -- general:
     primitive == 0.5.*,
-    base >= 4.5 && < 4.8
+    base-prelude == 0.1.*
   default-extensions:
     Arrows, BangPatterns, ConstraintKinds, DataKinds, DefaultSignatures, DeriveDataTypeable, DeriveFunctor, DeriveGeneric, EmptyDataDecls, FlexibleContexts, FlexibleInstances, FunctionalDependencies, GADTs, GeneralizedNewtypeDeriving, ImpredicativeTypes, LambdaCase, LiberalTypeSynonyms, MagicHash, MultiParamTypeClasses, MultiWayIf, NoImplicitPrelude, NoMonomorphismRestriction, OverloadedStrings, PatternGuards, ParallelListComp, QuasiQuotes, RankNTypes, RecordWildCards, ScopedTypeVariables, StandaloneDeriving, TemplateHaskell, TupleSections, TypeFamilies, TypeOperators, UnboxedTuples
   default-language: