diff --git a/LICENSE b/LICENSE
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--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,30 @@
+Copyright (c) 2017, Herbert Valerio Riedel
+
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+
+    * Redistributions in binary form must reproduce the above
+      copyright notice, this list of conditions and the following
+      disclaimer in the documentation and/or other materials provided
+      with the distribution.
+
+    * Neither the name of Herbert Valerio Riedel nor the names of other
+      contributors may be used to endorse or promote products derived
+      from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/Only.cabal b/Only.cabal
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--- /dev/null
+++ b/Only.cabal
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+name:                Only
+version:             0.1
+synopsis:            The 1-tuple type or single-value "collection"
+license:             BSD3
+license-file:        LICENSE
+author:              Herbert Valerio Riedel
+maintainer:          hvr@gnu.org
+bug-reports:         https://github.com/hvr/Only/issues
+category:            Data
+build-type:          Simple
+cabal-version:       >=1.10
+description:         This package provides the canonical anonymous 1-tuple type missing from Haskell for attaching typeclass instances.
+
+Source-Repository head
+  Type:              git
+  Location:          https://github.com/hvr/Only.git
+
+library
+  hs-source-dirs:    src
+  exposed-modules:   Data.Tuple.Only
+
+  default-language:  Haskell2010
+  other-extensions:  DeriveGeneric
+                   , DeriveDataTypeable
+                   , DeriveFunctor
+                   , Safe
+
+  build-depends:     base    >= 4.5 && <5
+                   , deepseq >= 1.1 && <1.5
+
+  if impl(ghc == 7.4.*)
+     build-depends: ghc-prim
diff --git a/Setup.hs b/Setup.hs
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--- /dev/null
+++ b/Setup.hs
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+import Distribution.Simple
+main = defaultMain
diff --git a/src/Data/Tuple/Only.hs b/src/Data/Tuple/Only.hs
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--- /dev/null
+++ b/src/Data/Tuple/Only.hs
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+{-# LANGUAGE DeriveDataTypeable #-}
+{-# LANGUAGE DeriveFunctor      #-}
+{-# LANGUAGE DeriveGeneric      #-}
+{-# LANGUAGE Safe               #-}
+
+module Data.Tuple.Only where
+
+import           Control.DeepSeq (NFData (rnf))
+import           Data.Data       (Data)
+import           Data.Typeable   (Typeable)
+import           GHC.Generics    (Generic)
+
+-- | The 1-tuple type or single-value "collection".
+--
+-- This type is structurally equivalent to the
+-- 'Data.Functor.Identity.Identity' type, but its intent is more
+-- about serving as the anonymous 1-tuple type missing from Haskell for attaching
+-- typeclass instances.
+--
+-- Parameter usage example:
+--
+-- @encodeSomething ('Only' (42::Int))@
+--
+-- Result usage example:
+--
+-- @xs <- decodeSomething
+--forM_ xs $ \\('Only' id) -> {- ... -}@
+--
+newtype Only a = Only { fromOnly :: a }
+               deriving (Eq, Ord, Read, Show, Generic, Functor, Data, Typeable)
+
+instance NFData a => NFData (Only a) where
+    rnf = rnf . fromOnly