diff --git a/Text/EditDistance.hs b/Text/EditDistance.hs
--- a/Text/EditDistance.hs
+++ b/Text/EditDistance.hs
@@ -2,7 +2,7 @@
 
 -- | Computing the edit distances between strings
 module Text.EditDistance ( 
-        EditCosts(..), defaultEditCosts, 
+        Costs(..), EditCosts(..), defaultEditCosts, 
         levenshteinDistance, restrictedDamerauLevenshteinDistance
     ) where
 
diff --git a/Text/EditDistance/EditCosts.hs b/Text/EditDistance/EditCosts.hs
--- a/Text/EditDistance/EditCosts.hs
+++ b/Text/EditDistance/EditCosts.hs
@@ -15,10 +15,10 @@
 cost (VariableCost f) x = f x
 
 data EditCosts = EditCosts {
-    deletionCosts :: Costs Char,
-    insertionCosts :: Costs Char,
-    substitutionCosts :: Costs (Char, Char),
-    transpositionCosts :: Costs (Char, Char)
+    deletionCosts :: Costs Char,             -- ^ Cost of deleting the specified character from the left string
+    insertionCosts :: Costs Char,            -- ^ Cost of inserting the specified characters into the right string
+    substitutionCosts :: Costs (Char, Char), -- ^ Cost of substituting a character from the left string with one from the right string -- with arguments in that order.
+    transpositionCosts :: Costs (Char, Char) -- ^ Cost of moving one character backwards and the other forwards -- with arguments in that order.
   }
 
 {-# INLINE deletionCost #-}
diff --git a/edit-distance.cabal b/edit-distance.cabal
--- a/edit-distance.cabal
+++ b/edit-distance.cabal
@@ -1,5 +1,5 @@
 Name:                edit-distance
-Version:             0.2.0
+Version:             0.2.1
 Cabal-Version:       >= 1.2
 Category:            Algorithms
 Synopsis:            Levenshtein and restricted Damerau-Levenshtein edit distances