diff --git a/CONTRIBUTORS.md b/CONTRIBUTORS.md
--- a/CONTRIBUTORS.md
+++ b/CONTRIBUTORS.md
@@ -7,8 +7,6 @@
 
 ## `prettyprinter` library (this one)
 
-- Moritz Kiefer, @cocreature
-- Daniel Mendler, @minad – several ideas after the preliminary release
 - David Luposchainsky, @quchen – current maintainer
 
 ## `ansi-wl-pprint` (origin forked from)
diff --git a/prettyprinter.cabal b/prettyprinter.cabal
--- a/prettyprinter.cabal
+++ b/prettyprinter.cabal
@@ -1,5 +1,5 @@
 name:                prettyprinter
-version:             1.0.1
+version:             1.1
 cabal-version:       >= 1.10
 category:            User Interfaces, Text
 synopsis:            A modern, easy to use, well-documented, extensible prettyprinter.
diff --git a/src/Data/Text/Prettyprint/Doc/Internal.hs b/src/Data/Text/Prettyprint/Doc/Internal.hs
--- a/src/Data/Text/Prettyprint/Doc/Internal.hs
+++ b/src/Data/Text/Prettyprint/Doc/Internal.hs
@@ -203,17 +203,6 @@
 instance Pretty a => Pretty (NonEmpty a) where
     pretty (x:|xs) = prettyList (x:xs)
 
--- | Does not change the text, but removes all annotations. __Pitfall__: since
--- this un-annotates its argument, nesting it means multiple, potentially
--- costly, traversals over the 'Doc'.
---
--- >>> pretty 123
--- 123
--- >>> pretty (pretty 123)
--- 123
-instance Pretty (Doc ann) where
-    pretty = unAnnotate
-
 -- | >>> pretty ()
 -- ()
 --
@@ -1314,7 +1303,7 @@
 -- entire contained document. If possible, it is preferrable to unannotate after
 -- producing the layout by using 'unAnnotateS'.
 unAnnotate :: Doc ann -> Doc xxx
-unAnnotate = alterAnnotations (const Nothing)
+unAnnotate = alterAnnotations (const [])
 
 -- | Change the annotation of a 'Doc'ument.
 --
@@ -1328,19 +1317,24 @@
 -- Since @'reAnnotate'@ has the right type and satisfies @'reAnnotate id = id'@,
 -- it is used to define the @'Functor'@ instance of @'Doc'@.
 reAnnotate :: (ann -> ann') -> Doc ann -> Doc ann'
-reAnnotate re = alterAnnotations (Just . re)
+reAnnotate re = alterAnnotations (pure . re)
 
--- | Change the annotation of a 'Doc'ument to a different one, or none at all.
+-- | Change the annotations of a 'Doc'ument. Individual annotations can be
+-- removed, changed, or replaced by multiple ones.
 --
 -- This is a general function that combines 'unAnnotate' and 'reAnnotate', and
 -- it is useful for mapping semantic annotations (such as »this is a keyword«)
--- to display annotations (such as »this is red«), because some backends may not
--- care about certain annotations, while others may.
+-- to display annotations (such as »this is red and underlined«), because some
+-- backends may not care about certain annotations, while others may.
 --
+-- Annotations earlier in the new list will be applied earlier, i.e. returning
+-- @[Bold, Green]@ will result in a bold document that contains green text, and
+-- not vice-versa.
+--
 -- Since this traverses the entire @'Doc'@ tree, including parts that are not
 -- rendered due to other layouts fitting better, it is preferrable to reannotate
 -- after producing the layout by using @'alterAnnotationsS'@.
-alterAnnotations :: (ann -> Maybe ann') -> Doc ann -> Doc ann'
+alterAnnotations :: (ann -> [ann']) -> Doc ann -> Doc ann'
 alterAnnotations re = go
   where
     go = \case
@@ -1357,10 +1351,14 @@
         Column f        -> Column (go . f)
         WithPageWidth f -> WithPageWidth (go . f)
         Nesting f       -> Nesting (go . f)
-        Annotated ann x -> case re ann of
-            Nothing   -> go x
-            Just ann' -> Annotated ann' (go x)
+        Annotated ann x -> foldr Annotated (go x) (re ann)
 
+-- $
+-- >>> let doc = "lorem" <+> annotate () "ipsum" <+> "dolor"
+-- >>> let re () = ["FOO", "BAR"]
+-- >>> layoutPretty defaultLayoutOptions (alterAnnotations re doc)
+-- SText 5 "lorem" (SChar ' ' (SAnnPush "FOO" (SAnnPush "BAR" (SText 5 "ipsum" (SAnnPop (SAnnPop (SChar ' ' (SText 5 "dolor" SEmpty))))))))
+
 -- | Remove all annotations. 'unAnnotate' for 'SimpleDocStream'.
 unAnnotateS :: SimpleDocStream ann -> SimpleDocStream xxx
 unAnnotateS = alterAnnotationsS (const Nothing)
@@ -1371,6 +1369,11 @@
 
 -- | Change the annotation of a document to a different annotation, or none at
 -- all. 'alterAnnotations' for 'SimpleDocStream'.
+--
+-- Note that the 'Doc' version is more flexible, since it allows changing a
+-- single annotation to multiple ones.
+-- ('Data.Text.Prettyprint.Doc.Render.Util.SimpleDocTree.SimpleDocTree' restores
+-- this flexibility again.)
 alterAnnotationsS :: (ann -> Maybe ann') -> SimpleDocStream ann -> SimpleDocStream ann'
 alterAnnotationsS re = go
   where
@@ -1777,8 +1780,6 @@
 -- indentation. Since no \'pretty\' printing is involved, this layouter is very
 -- fast. The resulting output contains fewer characters than a prettyprinted
 -- version and can be used for output that is read by other programs.
---
--- This layout function does not add any colorisation information.
 --
 -- >>> let doc = hang 4 (vsep ["lorem", "ipsum", hang 4 (vsep ["dolor", "sit"])])
 -- >>> doc
diff --git a/src/Data/Text/Prettyprint/Doc/Render/Util/SimpleDocTree.hs b/src/Data/Text/Prettyprint/Doc/Render/Util/SimpleDocTree.hs
--- a/src/Data/Text/Prettyprint/Doc/Render/Util/SimpleDocTree.hs
+++ b/src/Data/Text/Prettyprint/Doc/Render/Util/SimpleDocTree.hs
@@ -217,15 +217,19 @@
 
 -- | Remove all annotations. 'unAnnotate' for 'SimpleDocTree'.
 unAnnotateST :: SimpleDocTree ann -> SimpleDocTree xxx
-unAnnotateST = alterAnnotationsST (const Nothing)
+unAnnotateST = alterAnnotationsST (const [])
 
 -- | Change the annotation of a document. 'reAnnotate' for 'SimpleDocTree'.
 reAnnotateST :: (ann -> ann') -> SimpleDocTree ann -> SimpleDocTree ann'
-reAnnotateST f = alterAnnotationsST (Just . f)
+reAnnotateST f = alterAnnotationsST (pure . f)
 
 -- | Change the annotation of a document to a different annotation, or none at
 -- all. 'alterAnnotations' for 'SimpleDocTree'.
-alterAnnotationsST :: (ann -> Maybe ann') -> SimpleDocTree ann -> SimpleDocTree ann'
+--
+-- Note that this is as powerful as 'alterAnnotations', allowing one annotation
+-- to become multiple ones, contrary to 'alterAnnotationsS', which cannot do
+-- this.
+alterAnnotationsST :: (ann -> [ann']) -> SimpleDocTree ann -> SimpleDocTree ann'
 alterAnnotationsST re = go
   where
     go = \case
@@ -234,9 +238,7 @@
         STText l t     -> STText l t
         STLine i       -> STLine i
         STConcat xs    -> STConcat (map go xs)
-        STAnn ann rest -> case re ann of
-            Nothing   -> go rest
-            Just ann' -> STAnn ann' (go rest)
+        STAnn ann rest -> Prelude.foldr STAnn (go rest) (re ann)
 
 -- | Collect all annotations from a document.
 instance Foldable SimpleDocTree where