diff --git a/foreign-store.cabal b/foreign-store.cabal
--- a/foreign-store.cabal
+++ b/foreign-store.cabal
@@ -1,6 +1,6 @@
 name:                foreign-store
-version:             0.1
-synopsis:            Store a stable pointer in a foreign context to be retrieved later. Persists through GHCi reloads.
+version:             0.2
+synopsis:            Store a stable pointer in a foreign context to be retrieved later.
 description:         Store a stable pointer in a foreign context to be retrieved later. Persists through GHCi reloads.
 license:             BSD3
 license-file:        LICENSE
diff --git a/src/Foreign/Store.hs b/src/Foreign/Store.hs
--- a/src/Foreign/Store.hs
+++ b/src/Foreign/Store.hs
@@ -13,7 +13,8 @@
   ,deleteStore
   ,storeAction
   ,withStore
-  ,Store(..))
+  ,Store(..)
+  ,StoreException(..))
   where
 
 import Control.Exception
@@ -30,11 +31,13 @@
 instance Exception StoreException
 
 -- | A hideously unsafe store. Only for use if you are suave.
-data Store a =
+newtype Store a =
   Store Word32
   deriving (Show,Eq)
 
 -- | Lookup from the store if an index is allocated.
+--
+-- Not thread-safe.
 lookupStore :: Word32 -> IO (Maybe (Store a))
 lookupStore i =
   do r <- x_lookup i
@@ -45,6 +48,7 @@
 -- | Allocates or finds an unallocated store. The index is random. The
 -- internal vector of stores grows in size. When stores are deleted
 -- the vector does not shrink, but old slots are re-used.
+--
 -- Not thread-safe.
 newStore :: a -> IO (Store a)
 newStore a =
@@ -56,6 +60,7 @@
 -- creates one and resizes the store vector to fit. If there is
 -- already a store at the given index, deletes that store with
 -- 'deleteStore' before replacing it.
+--
 -- Not thread-safe.
 writeStore :: Store a -> a -> IO ()
 writeStore (Store i) a =
@@ -67,6 +72,7 @@
 
 -- | Read from the store. If the store has been deleted or is
 -- unallocated, this will throw an exception.
+--
 -- Not thread-safe.
 readStore :: Store a -> IO a
 readStore (Store i) =
@@ -76,7 +82,9 @@
         else deRefStablePtr sptr
 
 -- | Frees the stable pointer for GC and frees up the slot in the
--- store. Deleting an already deleted store is a no-op.
+-- store. Deleting an already deleted store is a no-op. But remember
+-- that store numbers are re-used.
+--
 -- Not thread-safe.
 deleteStore :: Store a -> IO ()
 deleteStore (Store i) = do
@@ -87,13 +95,17 @@
              x_delete i
 
 -- | Run the action and store the result.
+--
+-- Not thread-safe.
 storeAction :: Store a -> IO a -> IO a
 storeAction s m =
   do v <- m
      writeStore s v
      return v
 
--- | Run the action and store the result.
+-- | Run the action with the value in the store.
+--
+-- Not thread-safe.
 withStore :: Store a -> (a -> IO b) -> IO b
 withStore s f =
   do v <- readStore s