diff --git a/LIO/Web/Simple/Auth.hs b/LIO/Web/Simple/Auth.hs
--- a/LIO/Web/Simple/Auth.hs
+++ b/LIO/Web/Simple/Auth.hs
@@ -1,9 +1,16 @@
 {-# LANGUAGE Trustworthy #-}
 {-# LANGUAGE OverloadedStrings #-}
 
--- | Provides HTTP Basic Authentication.
-module LIO.Web.Simple.Auth ( basicAuth) where
+-- | Provides generic and HTTP Basic authentication.
+module LIO.Web.Simple.Auth ( basicAuth
+                           , handleAuth
+                           , requestLogin
+                           -- * Helpers
+                           , withUserOrLogin
+                           , currentUser
+                           ) where
 
+import Data.Maybe
 import Control.Monad
 import qualified Data.ByteString.Char8 as S8
 import Data.ByteString.Base64
@@ -13,24 +20,26 @@
 import Web.Simple.Controller.Trans
 
 
--- | A 'Route' that uses HTTP basic authentication to authenticate a
--- request for a realm with the given username ans password. The
--- request is rewritten with an 'X-User' header containing the
--- authenticated username before being passed to the next 'Route'.
+-- | A middleware that uses HTTP basic authentication to authenticate
+-- a request for a realm with the given username and password. The
+-- request is rewritten with an @X-User@ request header containing the
+-- authenticated username before being passed to the next
+-- 'application'. Note that the HTTP basic authentication header is
+-- only set if the executed app requests it, by setting the @X-Login@
+-- response header (e.g., with 'requestLogin').
 basicAuth :: Monad m
           => String                          -- ^ Realm
           -> (S8.ByteString -> S8.ByteString -> m Bool)
           -> SimpleMiddleware m
-basicAuth realm auth app req = 
-  case getBasicAuthLogin req of
-    Nothing -> return authResp
-    Just (usr, pwd) -> do
-      success <- auth usr pwd
-      let req' = req { requestHeaders = ("X-User", usr) : requestHeaders req }
-      if success
-        then app req'
-        else return authResp
-    where authResp = requireBasicAuth realm
+basicAuth realm auth app0 req0 = handleAuth authApp (mkApp app0) req0
+  where authApp = const . return $ requireBasicAuth realm
+        mkApp app req =  case getBasicAuthLogin req of
+          Nothing -> app req
+          Just (usr, pwd) -> do
+            success <- auth usr pwd
+            let req' = req { requestHeaders = ("X-User", usr) : 
+                                              requestHeaders req }
+            if success then app req' else app req
 
 
 -- | Helper method for implementing basic authentication. Given a
@@ -44,3 +53,32 @@
   case up of
      Right (user:pwd:[]) -> return (user, pwd)
      _ -> fail "Malformed basic auth header."
+
+-- | Executes the app and if the app 'Response' has header
+-- @X-Login@ and the user is not logged in, i.e., the @X-User@ request
+-- header is not present, execute the login application.
+handleAuth :: Monad m => SimpleApplication m -> SimpleMiddleware m
+handleAuth loginApp app req = do
+  resp <- app req
+  if hasLogin resp && notLoggedIn
+    then loginApp req
+    else return resp
+  where hasLogin r  = "X-Login" `isIn` responseHeaders r
+        notLoggedIn = not $ "X-User" `isIn` requestHeaders req
+        isIn n xs   = isJust $ lookup n xs
+
+-- | Request authentication middleware to authenticate user
+requestLogin :: Response
+requestLogin = responseLBS status400 [("X-Login", "True")] ""
+
+-- | Execute action with the current user's name. Otherwise, request
+-- that the user authenticate.
+withUserOrLogin :: Monad m 
+                => (S8.ByteString -> ControllerT m r a)
+                -> ControllerT m r a
+withUserOrLogin act = currentUser >>= \muser ->
+  maybe (respond requestLogin) act muser
+
+-- | Get the current user.
+currentUser :: Monad m => ControllerT m r (Maybe S8.ByteString)
+currentUser = requestHeader "X-User"
diff --git a/lio-simple.cabal b/lio-simple.cabal
--- a/lio-simple.cabal
+++ b/lio-simple.cabal
@@ -1,5 +1,5 @@
 name:                lio-simple
-version:             0.0.0.3
+version:             0.0.1.0
 synopsis:            LIO support for the Simple web framework
 description: