diff --git a/changelog b/changelog
--- a/changelog
+++ b/changelog
@@ -1,3 +1,7 @@
+0.1.6
+
+* Explicit `NoImplicitPrelude` on source files (issue #1).
+
 0.1.5
 
 * Compile with GHC 7.8
diff --git a/src/Sys/CmdSpec.hs b/src/Sys/CmdSpec.hs
--- a/src/Sys/CmdSpec.hs
+++ b/src/Sys/CmdSpec.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE NoImplicitPrelude #-}
 {-# LANGUAGE MultiParamTypeClasses #-}
 {-# LANGUAGE FlexibleInstances #-}
 
diff --git a/src/Sys/CreateProcess.hs b/src/Sys/CreateProcess.hs
--- a/src/Sys/CreateProcess.hs
+++ b/src/Sys/CreateProcess.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE NoImplicitPrelude #-}
 {-# LANGUAGE MultiParamTypeClasses #-}
 {-# LANGUAGE FlexibleInstances #-}
 
diff --git a/src/Sys/Exit.hs b/src/Sys/Exit.hs
--- a/src/Sys/Exit.hs
+++ b/src/Sys/Exit.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE NoImplicitPrelude #-}
+
 module Sys.Exit(
   module ExitCode
 , module Process
diff --git a/src/Sys/ExitCode.hs b/src/Sys/ExitCode.hs
--- a/src/Sys/ExitCode.hs
+++ b/src/Sys/ExitCode.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE NoImplicitPrelude #-}
+
 module Sys.ExitCode(
   ExitCode
 , _ExitFailure
diff --git a/src/Sys/Process.hs b/src/Sys/Process.hs
--- a/src/Sys/Process.hs
+++ b/src/Sys/Process.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE NoImplicitPrelude #-}
+
 module Sys.Process(
   module CmdSpec
 , module CreateProcess
diff --git a/src/Sys/StdStream.hs b/src/Sys/StdStream.hs
--- a/src/Sys/StdStream.hs
+++ b/src/Sys/StdStream.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE NoImplicitPrelude #-}
 {-# LANGUAGE MultiParamTypeClasses #-}
 {-# LANGUAGE FlexibleInstances #-}
 
diff --git a/sys-process.cabal b/sys-process.cabal
--- a/sys-process.cabal
+++ b/sys-process.cabal
@@ -1,5 +1,5 @@
 name:               sys-process
-version:            0.1.5
+version:            0.1.6
 license:            BSD3
 license-file:       LICENSE
 author:             Tony Morris <ʇǝu˙sıɹɹoɯʇ@ןןǝʞsɐɥ> <dibblego>
diff --git a/test/doctests.hs b/test/doctests.hs
--- a/test/doctests.hs
+++ b/test/doctests.hs
@@ -1,7 +1,11 @@
+{-# LANGUAGE CPP #-}
+
 module Main where
 
+#if !(MIN_VERSION_base(4,8,0))
+import Control.Applicative(Applicative((<*>), pure))
+#endif
 import Build_doctests (deps)
-import Control.Applicative
 import Control.Monad
 import Data.List
 import System.Directory