diff --git a/ot.cabal b/ot.cabal
--- a/ot.cabal
+++ b/ot.cabal
@@ -1,5 +1,5 @@
 Name:                ot
-Version:             0.1.2.2
+Version:             0.2.0.0
 Synopsis:            Real-time collaborative editing with Operational Transformation
 -- A longer description of the package.
 -- Description:         
@@ -19,13 +19,16 @@
 Library
   Ghc-options:         -Wall
   Hs-source-dirs:      src
-  Exposed-modules:     Control.OperationalTransformation, Control.OperationalTransformation.List, Control.OperationalTransformation.Text, Control.OperationalTransformation.Properties, Control.OperationalTransformation.Client, Control.OperationalTransformation.Server
+  Exposed-modules:     Control.OperationalTransformation, Control.OperationalTransformation.List, Control.OperationalTransformation.Text, Control.OperationalTransformation.Selection, Control.OperationalTransformation.Properties, Control.OperationalTransformation.Client, Control.OperationalTransformation.Server
   Build-depends:       base >= 4 && < 5,
                        text >= 1.0 && < 1.3,
                        aeson >= 0.7 && < 0.9,
                        attoparsec >= 0.10.1.1 && < 1,
                        QuickCheck >= 2.7 && < 2.8,
-                       binary >= 0.6.0.0 && < 0.8
+                       binary >= 0.5.1.1 && < 0.8,
+                       either >= 4.1.2 && < 5,
+                       mtl >= 2.1.3.1 && < 3,
+                       ghc
 
   -- Modules not exported by this package.
   -- Other-modules:       
@@ -34,7 +37,7 @@
   Ghc-options:         -Wall -rtsopts
   Hs-source-dirs:      test
   type:                exitcode-stdio-1.0
-  main-is:             TestSuite.hs
+  main-is:             Main.hs
   Build-depends:       ot,
                        QuickCheck,
                        HUnit,
diff --git a/src/Control/OperationalTransformation.hs b/src/Control/OperationalTransformation.hs
--- a/src/Control/OperationalTransformation.hs
+++ b/src/Control/OperationalTransformation.hs
@@ -3,6 +3,7 @@
 module Control.OperationalTransformation
   ( OTOperation (..)
   , OTComposableOperation (..)
+  , OTCursor (..)
   , OTSystem (..)
   ) where
 
@@ -38,11 +39,35 @@
         (os', ps'') <- transformList2 os ps'
         return (o':os', ps'')
 
+-- | Cursor position
+class OTCursor cursor op where
+  updateCursor :: op -> cursor -> cursor
+
+
 instance (OTOperation op) => OTComposableOperation [op] where
   compose a b = return $ a ++ b
 
 instance (OTSystem doc op) => OTSystem doc [op] where
   apply = flip $ foldM $ flip apply
+
+
+instance OTCursor () op where
+  updateCursor _ _ = ()
+
+instance OTCursor cursor op => OTCursor [cursor] op where
+  updateCursor op = map (updateCursor op)
+
+instance (OTCursor a op, OTCursor b op) => OTCursor (a, b) op where
+  updateCursor op (a, b) = (updateCursor op a, updateCursor op b)
+
+instance (OTCursor a op, OTCursor b op, OTCursor c op) => OTCursor (a, b, c) op where
+  updateCursor op (a, b, c) = (updateCursor op a, updateCursor op b, updateCursor op c)
+
+instance (OTCursor a op, OTCursor b op, OTCursor c op, OTCursor d op) => OTCursor (a, b, c, d) op where
+  updateCursor op (a, b, c, d) = (updateCursor op a, updateCursor op b, updateCursor op c, updateCursor op d)
+
+instance (OTCursor a op, OTCursor b op, OTCursor c op, OTCursor d op, OTCursor e op) => OTCursor (a, b, c, d, e) op where
+  updateCursor op (a, b, c, d, e) = (updateCursor op a, updateCursor op b, updateCursor op c, updateCursor op d, updateCursor op e)
 
 
 instance (OTOperation a, OTOperation b) => OTOperation (a, b) where
diff --git a/src/Control/OperationalTransformation/Selection.hs b/src/Control/OperationalTransformation/Selection.hs
new file mode 100644
--- /dev/null
+++ b/src/Control/OperationalTransformation/Selection.hs
@@ -0,0 +1,93 @@
+{-# LANGUAGE CPP, TypeFamilies, OverloadedStrings #-}
+{-# LANGUAGE GeneralizedNewtypeDeriving, MultiParamTypeClasses #-}
+
+module Control.OperationalTransformation.Selection
+  ( Range (..)
+  , Selection (..)
+  , createCursor
+  , size
+  , somethingSelected
+  ) where
+
+import Control.OperationalTransformation
+import Control.OperationalTransformation.Text
+import Data.Aeson
+import Control.Applicative
+import Data.Monoid
+import Data.List (sort)
+import qualified Data.Text as T
+#if MIN_VERSION_ghc(7,8,0)
+import GHC.Exts (IsList (..))
+#endif
+
+-- | Range has `anchor` and `head` properties, which are zero-based indices into
+-- the document. The `anchor` is the side of the selection that stays fixed,
+-- `head` is the side of the selection where the cursor is. When both are
+-- equal, the range represents a cursor.
+data Range = Range { rangeAnchor :: !Int, rangeHead :: !Int }
+  deriving (Show, Read, Eq, Ord)
+
+instance ToJSON Range where
+  toJSON (Range a h) = object [ "anchor" .= a, "head" .= h ]
+
+instance FromJSON Range where
+  parseJSON (Object o) = Range <$> o .: "anchor" <*> o .: "head"
+  parseJSON _ = fail "expected an object"
+
+instance OTCursor Range TextOperation where
+  updateCursor (TextOperation actions) (Range a h) = Range a' h'
+    where
+      a' = updateComponent a
+      h' = if a == h then a' else updateComponent h
+      updateComponent c = loop c c actions
+      loop :: Int -> Int -> [Action] -> Int
+      loop oldIndex newIndex as
+        | oldIndex < 0 = newIndex
+        | otherwise =
+          case as of
+            (op:ops) -> case op of
+              Retain r -> loop (oldIndex-r) newIndex ops
+              Insert i -> loop oldIndex (newIndex + T.length i) ops
+              Delete d -> loop (oldIndex-d) (newIndex - min oldIndex d) ops
+            _ -> newIndex -- matching on `[]` gives a non-exhaustive pattern
+                          -- match warning for some reason
+
+-- | A selection consists of a list of ranges. Each range may represent a
+-- selected part of the document or a cursor in the document.
+newtype Selection = Selection { ranges :: [Range] }
+  deriving (Monoid, Show, Read)
+
+instance OTCursor Selection TextOperation where
+  updateCursor op = Selection . updateCursor op . ranges
+
+instance Eq Selection where
+  Selection rs1 == Selection rs2 = sort rs1 == sort rs2
+
+instance Ord Selection where
+  Selection rs1 `compare` Selection rs2 = sort rs1 `compare` sort rs2
+
+instance ToJSON Selection where
+  toJSON (Selection rs) = object [ "ranges" .= rs ]
+
+instance FromJSON Selection where
+  parseJSON (Object o) = Selection <$> o .: "ranges"
+  parseJSON _ = fail "expected an object"
+
+#if MIN_VERSION_ghc(7,8,0)
+instance IsList Selection where
+  type Item Selection = Range
+  fromList = Selection
+  toList = ranges
+#endif
+
+-- | Create a selection that represents a cursor.
+createCursor :: Int -> Selection
+createCursor i = Selection [Range i i]
+
+-- | Does the selection contain any characters?
+somethingSelected :: Selection -> Bool
+somethingSelected = any (\r -> rangeAnchor r /= rangeHead r) . ranges
+
+-- | Number of selected characters
+size :: Selection -> Int
+size = sum . map (\r -> abs (rangeAnchor r - rangeHead r)) . ranges
diff --git a/src/Control/OperationalTransformation/Server.hs b/src/Control/OperationalTransformation/Server.hs
--- a/src/Control/OperationalTransformation/Server.hs
+++ b/src/Control/OperationalTransformation/Server.hs
@@ -6,7 +6,8 @@
   ) where
 
 import Control.OperationalTransformation
-import Control.Monad (foldM)
+import Control.Monad.Trans.Either
+import Control.Monad.Identity
 
 type Revision = Integer
 
@@ -18,27 +19,31 @@
 initialServerState doc = ServerState 0 doc []
 
 -- | Handles incoming operations.
-applyOperation :: (OTSystem doc op)
+applyOperation :: (OTSystem doc op, OTCursor cursor op)
                => ServerState doc op
                -> Revision
                -- ^ The latest operation that the client has received from the server when it sent the operation.
                -> op
                -- ^ The operation received from the client.
-               -> Either String (op, ServerState doc op)
-               -- ^ The operation to broadcast to all connected clients
-               -- (except the client which has created the operation; that
-               -- client must be sent an acknowledgement) and the new state
-               -- (or an error).
-applyOperation (ServerState rev doc ops) oprev op = do
-  concurrentOps <- if oprev > rev || rev - oprev > fromIntegral (length ops)
-    then Left "unknown revision number"
-    else Right $ take (fromInteger $ rev - oprev) ops
-  op' <- foldM transformFst op (reverse concurrentOps)
-  doc' <- case apply op' doc of
-    Left err -> Left $ "apply failed: " ++ err
-    Right d -> Right d
-  return $ (op', ServerState (rev+1) doc' (op':ops))
-  where
-    transformFst a b = case transform a b of
-      Left err -> Left $ "transform failed: " ++ err
-      Right (a', _) -> Right a'
+               -> cursor
+               -- ^ The clients cursor position after the operation. (Use @()@
+               -- if not needed.)
+               -> Either String (op, cursor, ServerState doc op)
+               -- ^ The operation and the cursor to broadcast to all
+               -- connected clients  (except the client which has created the
+               -- operation; that client must be sent an acknowledgement) and
+               -- the new state (or an error).
+applyOperation (ServerState rev doc ops) oprev op cursor =
+  runIdentity $ runEitherT $ do
+    concurrentOps <- if oprev > rev || rev - oprev > fromIntegral (length ops)
+      then fail "unknown revision number"
+      else return $ take (fromInteger $ rev - oprev) ops
+    (op', cursor') <- foldM transformFst (op, cursor) (reverse concurrentOps)
+    doc' <- case apply op' doc of
+      Left err -> fail $ "apply failed: " ++ err
+      Right d -> return d
+    return $ (op', cursor', ServerState (rev+1) doc' (op':ops))
+    where
+      transformFst (a, curs) b = case transform a b of
+        Left err -> fail $ "transform failed: " ++ err
+        Right (a', _) -> return (a', updateCursor op curs)
diff --git a/src/Control/OperationalTransformation/Text.hs b/src/Control/OperationalTransformation/Text.hs
--- a/src/Control/OperationalTransformation/Text.hs
+++ b/src/Control/OperationalTransformation/Text.hs
@@ -1,4 +1,6 @@
-{-# LANGUAGE OverloadedStrings, MultiParamTypeClasses, GeneralizedNewtypeDeriving, DeriveDataTypeable, FlexibleInstances, FlexibleContexts, UndecidableInstances #-}
+{-# LANGUAGE CPP, OverloadedStrings, MultiParamTypeClasses #-}
+{-# LANGUAGE GeneralizedNewtypeDeriving, DeriveDataTypeable, FlexibleInstances #-}
+{-# LANGUAGE FlexibleContexts, UndecidableInstances, TypeFamilies #-}
 
 module Control.OperationalTransformation.Text
   (
@@ -6,21 +8,19 @@
     Action (..)
   , TextOperation (..)
   , invertOperation
-    -- * Text operations augmented with cursor information
-  , Cursor (..)
-  , updateCursor
-  , AugmentedTextOperation (..)
   ) where
 
 import Control.OperationalTransformation
 import qualified Data.Text as T
 import Data.Monoid (mappend)
-import Data.Aeson (Value (..), FromJSON (..), ToJSON (..), (.=), object, (.:))
+import Data.Aeson (Value (..), FromJSON (..), ToJSON (..))
 import Data.Binary (Binary (..), putWord8, getWord8)
 import Data.Typeable (Typeable)
 import Data.Text (pack, unpack)
-import Control.Applicative ((<$>), (<*>))
-
+import Control.Applicative ((<$>))
+#if MIN_VERSION_ghc(7,8,0)
+import GHC.Exts (IsList (..))
+#endif
 
 -- | An action changes the text at the current position or advances the cursor.
 data Action = Retain !Int    -- ^ Skip the next n characters.
@@ -60,6 +60,13 @@
 -- document.
 newtype TextOperation = TextOperation [Action] deriving (Read, Show, Binary, Typeable, FromJSON, ToJSON)
 
+#if MIN_VERSION_ghc(7,8,0)
+instance IsList TextOperation where
+  type Item TextOperation = Action
+  fromList = TextOperation
+  toList (TextOperation as) = as
+#endif
+
 addRetain :: Int -> [Action] -> [Action]
 addRetain n (Retain m : xs) = Retain (n+m) : xs
 addRetain n xs = Retain n : xs
@@ -74,7 +81,7 @@
 addDelete n xs = Delete n : xs
 
 -- | Merges actions, removes empty ops and makes insert ops come before delete
--- ops. Propertys:
+-- ops. Properties:
 --
 --     * Idempotence: @canonicalize op = canonicalize (canonicalize op)@
 --
@@ -169,8 +176,8 @@
       loop _ _ _ = Left "operation can't be applied to the document: text is longer than the operation"
 
 -- | Computes the inverse of an operation. Useful for implementing undo.
-invertOperation :: TextOperation               -- ^ An operation.
-                -> T.Text                      -- ^ Document before the operation was applied.
+invertOperation :: TextOperation               -- ^ An operation
+                -> T.Text                      -- ^ Document to apply the operation to
                 -> Either String TextOperation
 invertOperation (TextOperation actions) doc = loop actions doc []
   where
@@ -181,57 +188,3 @@
                     in loop ops after (Insert before : inv)
     loop [] "" inv = Right . TextOperation . reverse $ inv
     loop [] _ _ = Left "invert failed: text is longer than the operation"
-
--- | A cursor has a 'cursorPosition' and a 'cursorSelectionEnd'. Both are
--- zero-based indexes into the document. When nothing is selected,
--- 'cursorSelectionEnd' is equal to 'cursorPosition'. When there is a selection,
--- 'cursorPosition' is always the side of the selection that would move if you
--- pressed an arrow key.
-data Cursor = Cursor { cursorPosition, cursorSelectionEnd :: Int } deriving (Eq, Show, Read)
-
--- | Update cursor with respect to an operation.
-updateCursor :: Cursor -> TextOperation -> Cursor
-updateCursor (Cursor p s) (TextOperation actions) = Cursor transformedP transformedS
-  where
-    transformedP = transformComponent p
-    transformedS = if p == s then transformedP else transformComponent s
-    transformComponent c = loop c c actions
-    loop oldIndex newIndex _ | oldIndex < 0 = newIndex
-    loop _ newIndex [] = newIndex
-    loop oldIndex newIndex (op:ops) = case op of
-      Retain r -> loop (oldIndex-r) newIndex ops
-      Insert i -> loop oldIndex (newIndex + T.length i) ops
-      Delete d -> loop (oldIndex-d) (newIndex - min oldIndex d) ops
-
-instance ToJSON Cursor where
-  toJSON (Cursor p s) = object [ "position" .= p, "selectionEnd" .= s ]
-
-instance FromJSON Cursor where
-  parseJSON (Object o) = Cursor <$> o .: "position" <*> o .: "selectionEnd"
-  parseJSON _ = fail "expected an object"
-
--- | An operation bundled with the cursor position after the operation.
-data AugmentedTextOperation = AugmentedTextOperation
-  { augmentedCursor    :: Cursor
-  , augmentedOperation :: TextOperation
-  } deriving (Eq, Show, Read)
-
-instance ToJSON AugmentedTextOperation where
-  toJSON (AugmentedTextOperation cursor textOp) = object [ "cursor" .= cursor, "operation" .= textOp ]
-
-instance FromJSON AugmentedTextOperation where
-  parseJSON (Object o) = AugmentedTextOperation <$> o .: "cursor" <*> o .: "operation"
-  parseJSON _ = fail "expected an object"
-
-instance OTOperation AugmentedTextOperation where
-  transform (AugmentedTextOperation cursorA opA) (AugmentedTextOperation cursorB opB) = do
-    (opA', opB') <- transform opA opB
-    return ( AugmentedTextOperation (updateCursor cursorA opB') opA'
-           , AugmentedTextOperation (updateCursor cursorB opA') opB'
-           )
-
-instance OTComposableOperation AugmentedTextOperation where
-  compose (AugmentedTextOperation _ a) (AugmentedTextOperation cursor b) = AugmentedTextOperation cursor <$> compose a b
-
-instance (OTSystem doc TextOperation) => OTSystem doc AugmentedTextOperation where
-  apply (AugmentedTextOperation _ textOp) = apply textOp
diff --git a/test/Main.hs b/test/Main.hs
new file mode 100644
--- /dev/null
+++ b/test/Main.hs
@@ -0,0 +1,14 @@
+module Main (main) where
+
+import Test.Framework
+
+import qualified Control.OperationalTransformation.Text.Tests
+import qualified Control.OperationalTransformation.Selection.Tests
+import qualified Control.OperationalTransformation.ClientServerTests
+
+main :: IO ()
+main = defaultMain
+  [ Control.OperationalTransformation.Text.Tests.tests
+  , Control.OperationalTransformation.Selection.Tests.tests
+  , Control.OperationalTransformation.ClientServerTests.tests
+  ]
diff --git a/test/TestSuite.hs b/test/TestSuite.hs
deleted file mode 100644
--- a/test/TestSuite.hs
+++ /dev/null
@@ -1,10 +0,0 @@
-import Test.Framework
-
-import qualified Control.OperationalTransformation.Text.Tests
-import qualified Control.OperationalTransformation.ClientServerTests
-
-main :: IO ()
-main = defaultMain
-  [ Control.OperationalTransformation.Text.Tests.tests
-  , Control.OperationalTransformation.ClientServerTests.tests
-  ]