diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,3 +1,7 @@
+## 0.4.11
+
+* Export renderAddress as a utility (e.g. Reply-to) [#44](https://github.com/snoyberg/mime-mail/pull/44)
+
 ## 0.4.10
 
 * addParts: append mail parts to a Mail [#43](https://github.com/snoyberg/mime-mail/pull/43)
diff --git a/Network/Mail/Mime.hs b/Network/Mail/Mime.hs
--- a/Network/Mail/Mime.hs
+++ b/Network/Mail/Mime.hs
@@ -28,6 +28,7 @@
     , addAttachments
     , addAttachmentBS
     , addAttachmentsBS
+    , renderAddress
     , htmlPart
     , plainPart
     , randomString
@@ -216,6 +217,15 @@
         , fromByteString "\n"
         , finalBuilder
         ]
+
+-- | Format an E-Mail address according to the name-addr form (see: RFC5322
+-- § 3.4 "Address specification", i.e: [display-name] '<'addr-spec'>')
+-- This can be handy for adding custom headers that require such format.
+--
+-- @since 0.4.11
+renderAddress :: Address -> Text
+renderAddress address =
+    TE.decodeUtf8 $ toByteString $ showAddress address
 
 showHeader :: (S.ByteString, Text) -> Builder
 showHeader (k, v) = mconcat
diff --git a/mime-mail.cabal b/mime-mail.cabal
--- a/mime-mail.cabal
+++ b/mime-mail.cabal
@@ -1,5 +1,5 @@
 Name:                mime-mail
-Version:             0.4.10
+Version:             0.4.11
 Synopsis:            Compose MIME email messages.
 description:         Hackage documentation generation is not reliable. For up to date documentation, please see: <http://www.stackage.org/package/mime-mail>.
 Homepage:            http://github.com/snoyberg/mime-mail
@@ -30,6 +30,7 @@
 test-suite tests
     type: exitcode-stdio-1.0
     main-is: Spec.hs
+    other-modules: Network.Mail.MimeSpec
     hs-source-dirs: test
 
     build-depends: base
diff --git a/test/Network/Mail/MimeSpec.hs b/test/Network/Mail/MimeSpec.hs
new file mode 100644
--- /dev/null
+++ b/test/Network/Mail/MimeSpec.hs
@@ -0,0 +1,66 @@
+{-# LANGUAGE OverloadedStrings #-}
+module Network.Mail.MimeSpec where
+
+import Test.Hspec
+import Test.Hspec.QuickCheck
+import Network.Mail.Mime
+import qualified Data.ByteString.Lazy.Char8 as L8
+import Blaze.ByteString.Builder (toLazyByteString)
+import Control.Monad (forM_)
+import Data.Text.Lazy.Encoding (encodeUtf8)
+
+spec :: Spec
+spec = describe "Network.Mail.Mime" $ do
+    describe "quotedPrintable" $ do
+        it "doesn't generate lines longer than 76 characters" $ do
+            let lbs = toLazyByteString
+                    $ quotedPrintable True (L8.replicate 1000 'x')
+            forM_ (lines' lbs) $ (\l -> L8.length l `shouldSatisfy` (<= 76))
+        it "under 76 in presence of terminating space" $ do
+            let lbs = toLazyByteString
+                    $ quotedPrintable True
+                    $ L8.pack
+                    $ foldr
+                        (\a b -> b ++ replicate 74 'x' ++ [a])
+                        ""
+                        [' ']
+            forM_ (lines' lbs) $ (\l -> L8.length l `shouldSatisfy` (<= 76))
+        prop "always under 76 characters, text" $ \s ->
+            let orig = L8.pack s
+                gen = toLazyByteString $ quotedPrintable True orig
+             in all (\l -> L8.length l <= 76) $ lines' gen
+        prop "always under 76 characters, binary" $ \s ->
+            let orig = L8.pack s
+                gen = toLazyByteString $ quotedPrintable True orig
+             in all (\l -> L8.length l <= 76) $ lines' gen
+
+        it "example from Wikipedia" $
+            let enc = "If you believe that truth=3Dbeauty, then surely mathematics is the most bea=\r\nutiful branch of philosophy=2E"
+                dec = "If you believe that truth=beauty, then surely mathematics is the most beautiful branch of philosophy."
+             in toLazyByteString (quotedPrintable True dec) `shouldBe` enc
+
+        it "issue #17- as text" $
+            let enc = "</a>=E3=81=AB=E3=81=A4=E3=81=84=E3=81=A6=E3=81=AE=E3=83=86=E3=82=B9=E3=83=\r\n=88"
+                dec = encodeUtf8 "</a>についてのテスト"
+             in toLazyByteString (quotedPrintable True dec) `shouldBe` enc
+
+        it "issue #17- as binary" $
+            let enc = "</a>=E3=81=AB=E3=81=A4=E3=81=84=E3=81=A6=E3=81=AE=E3=83=86=E3=82=B9=E3=83=\r\n=88"
+                dec = encodeUtf8 "</a>についてのテスト"
+             in toLazyByteString (quotedPrintable False dec) `shouldBe` enc
+
+        it "concrete example: over 76 characters" $
+            let orig = "\240\238\191aa\149aa\226a\235\255a=aa\SI\159a\187a\147aa\ACKa\184aaaaaa\191a\237aaaa\EM a"
+                gen = toLazyByteString $ quotedPrintable True orig
+             in if all (\l -> L8.length l <= 76) $ lines' gen
+                    then True
+                    else error $ show $ lines' gen
+
+lines' :: L8.ByteString -> [L8.ByteString]
+lines' =
+    map stripCR . L8.lines
+  where
+    stripCR bs
+        | L8.null bs = bs
+        | L8.last bs == '\r' = L8.init bs
+        | otherwise = bs