diff --git a/System/USB/Safe.hs b/System/USB/Safe.hs
--- a/System/USB/Safe.hs
+++ b/System/USB/Safe.hs
@@ -58,8 +58,12 @@
     ( -- * Device regions
       DeviceRegionT
     , runDeviceRegionT
-    , forkDeviceRegionT
 
+    , TopDeviceRegion
+    , runTopDeviceRegion
+
+    , forkTopDeviceRegion
+
     , mapDeviceRegionT
     , liftCatch
 
@@ -361,16 +365,28 @@
 runDeviceRegionT ∷ MonadCatchIO m ⇒ (∀ s. DeviceRegionT s m α) → m α
 runDeviceRegionT m = runWith [] m
 
-{-| Execute the given region in a new thread.
+{-| A region which does not have parent regions and can be directly executed in
+'IO' by 'runTopDeviceRegion' or concurrently executed in another region by
+'forkTopDeviceRegion'.
+-}
+type TopDeviceRegion s = DeviceRegionT s IO
 
+-- | Convenience funtion for running a /top-level/ region in 'IO'.
+--
+-- Note that: @runTopDeviceRegion = 'runDeviceRegionT'@
+runTopDeviceRegion ∷ (∀ s. TopDeviceRegion s α) → IO α
+runTopDeviceRegion = runDeviceRegionT
+
+{-| Return a region which executes the given /top-level/ region in a new thread.
+
 Note that the forked region has the same type variable @s@ as the resulting
 region. This means that all 'DeviceHandle's which can be referenced in the
 resulting region can also be referenced in the forked region.
 -}
-forkDeviceRegionT ∷ MonadIO m
-                  ⇒ DeviceRegionT s IO ()
-                  → DeviceRegionT s m ThreadId
-forkDeviceRegionT m = DeviceRegionT $ do
+forkTopDeviceRegion ∷ MonadIO m
+                    ⇒ TopDeviceRegion s ()
+                    → DeviceRegionT s m ThreadId
+forkTopDeviceRegion m = DeviceRegionT $ do
   openedDevicesIORef ← ask
   liftIO $ do openedDevices ← readIORef openedDevicesIORef
               block $ do mapM_ incrementRefCnt openedDevices
@@ -729,7 +745,8 @@
 
  * 'NoDeviceException' if the device has been disconnected
 
- * 'SettingAlreadySet' if a configuration has already been set.
+ * 'SettingAlreadySet' if a configuration has already been set using
+   'withConfig' or 'withActiveConfig'.
 
  * Another 'USBException'.
 -}
@@ -1192,7 +1209,7 @@
 
 {-| Control transfers can have three request types: @Standard@, @Class@ and
 @Vendor@. We disallow @Standard@ requests however because with them you can
-destrow the safety guarantees that this module provides.
+destroy the safety guarantees that this module provides.
 -}
 data RequestType = Class | Vendor
 
diff --git a/usb-safe.cabal b/usb-safe.cabal
--- a/usb-safe.cabal
+++ b/usb-safe.cabal
@@ -1,5 +1,5 @@
 name:          usb-safe
-version:       0.1
+version:       0.2
 cabal-version: >=1.6
 build-type:    Simple
 license:       BSD3
@@ -10,6 +10,73 @@
 stability:     experimental
 category:      System
 synopsis:      Wrapper around the usb package adding extra type-safety
+description:
+  The usb library provides a standard Haskell abstracting layer over
+  bindings-libusb providing: abstract types instead of Ptrs, automatic
+  marshalling and unmarshalling, automatic garbage collection,
+  exceptions instead of integer return codes, etc..
+
+  .
+
+  While all that is very nice there are still some things that you can
+  do wrong. For example doing I/O with a closed device or reading from
+  or writing to an endpoint which doesn't belong to the claimed
+  interface. Or reading from an Out endpoint or writing to an In
+  endpoint.
+
+  .
+
+  usb-safe provides the following guarantees:
+
+  .
+
+  * You can't reference handles to devices that are closed. In other words: no
+     I/O with closed handles is possible.
+
+  .
+
+  * The programmer specifies the region in which devices should remain open. On
+    exit from the region the opened devices are automatically closed.
+
+  .
+
+  * You can't reference handles to configurations that have not been set.
+
+  .
+
+  * You can't reference handles to interfaces that have not been claimed.
+
+  .
+
+  * You can't reference handles to alternates that have not been set.
+
+  .
+
+  * You can't reference endpoints that don't belong to a setted alternate.
+
+  .
+
+  * You can't read from an endpoint with an Out transfer direction.
+
+  .
+
+  * You can't write to an endpoint with an In transfer direction.
+
+  .
+
+  * You can't read from or write to endpoints with the unsupported transfer
+    types Control and Isochronous. Only I/O with endpoints with the Bulk and
+    Interrupt transfer types is allowed.
+
+  .
+
+  The primary technique used in usb-safe is called \"Lightweight monadic
+  regions\" which was invented by Oleg Kiselyov and Chung-chieh Shan.
+  See:
+
+  .
+
+  <http://okmij.org/ftp/Haskell/regions.html#light-weight>
 
 source-repository head
   Type:     darcs