diff --git a/Data/Functor/Contravariant.hs b/Data/Functor/Contravariant.hs
new file mode 100644
--- /dev/null
+++ b/Data/Functor/Contravariant.hs
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+module Data.Functor.Contravariant where
+
+import Prelude hiding (Functor)
+
+import Control.Applicative.Backwards
+import Control.Arrow
+import Control.Monad.Trans.Except
+import Control.Monad.Trans.Reader
+import Control.Monad.Trans.State
+import Control.Monad.Trans.Writer
+import Data.Function (on)
+import qualified Data.Functor as Covar
+import Data.Functor.Compose
+import Data.Functor.Const
+import Data.Functor.Product
+import Data.Functor.Reverse
+import Data.Functor.Sum
+import Data.Monoid (Alt (..))
+import Data.Proxy
+
+class Functor f where
+    gmap :: (a -> b) -> f b -> f a
+    (>$) :: b -> f b -> f a
+    (>$) = gmap . const
+
+(>$<) :: Functor f => (a -> b) -> f b -> f a
+(>$<) = gmap
+
+newtype Op1 b a = Op1 { op1 :: a -> b }
+newtype Op2 b a = Op2 { op2 :: a -> a -> b }
+
+instance Functor (Op1 a) where gmap f (Op1 g) = Op1 (g . f)
+instance Functor (Op2 a) where gmap f (Op2 g) = Op2 (g `on` f)
+instance Functor (Const a) where gmap _ (Const a) = Const a
+instance Functor Proxy where gmap _ Proxy = Proxy
+instance (Functor f, Functor g) => Functor (Product f g) where
+    gmap f (Pair x y) = Pair (f >$< x) (f >$< y)
+instance (Functor f, Functor g) => Functor (Sum f g) where
+    gmap f (InL x) = InL (f >$< x)
+    gmap f (InR y) = InR (f >$< y)
+deriving instance Functor f => Functor (Reverse f)
+deriving instance Functor f => Functor (Backwards f)
+deriving instance Functor f => Functor (Alt f)
+instance Functor f => Functor (ExceptT e f) where gmap f = ExceptT . gmap (fmap f) . runExceptT
+instance Functor f => Functor (ReaderT r f) where gmap f = ReaderT . fmap (gmap f) . runReaderT
+instance Functor f => Functor (StateT  s f) where
+    gmap f = StateT  . (fmap . gmap) (f *** id) . runStateT
+instance Functor f => Functor (WriterT w f) where gmap f = WriterT . gmap (f *** id) . runWriterT
diff --git a/Data/Profunctor.hs b/Data/Profunctor.hs
new file mode 100644
--- /dev/null
+++ b/Data/Profunctor.hs
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+module Data.Profunctor where
+
+import Prelude hiding ((.), id)
+
+import Control.Arrow (Kleisli (..))
+import Control.Category
+import Control.Monad
+
+class Profunctor p where
+    dimap :: (a -> b) -> (c -> d) -> p b c -> p a d
+    dimap f g = lmap f . rmap g
+
+    lmap :: (a -> b) -> p b c -> p a c
+    lmap f = dimap f id
+
+    rmap :: (b -> c) -> p a b -> p a c
+    rmap g = dimap id g
+
+instance Profunctor (->) where
+    dimap f g a = g . a . f
+
+instance Monad m => Profunctor (Kleisli m) where
+    dimap f g (Kleisli a) = Kleisli (fmap g . a . f)
diff --git a/LICENSE b/LICENSE
new file mode 100644
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,30 @@
+Copyright (c) 2017, M Farkas-Dyck
+
+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 M Farkas-Dyck 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/Setup.hs b/Setup.hs
new file mode 100644
--- /dev/null
+++ b/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/hs-functors.cabal b/hs-functors.cabal
new file mode 100644
--- /dev/null
+++ b/hs-functors.cabal
@@ -0,0 +1,24 @@
+name:                hs-functors
+version:             0.1.0.0
+synopsis:            Functors from products of Haskell and its dual to Haskell
+-- description:         
+license:             BSD3
+license-file:        LICENSE
+author:              M Farkas-Dyck
+maintainer:          m.farkasdyck@gmail.com
+-- copyright:           
+category:            Math
+build-type:          Simple
+cabal-version:       >=1.10
+
+library
+  exposed-modules:     Data.Functor.Contravariant
+  exposed-modules:     Data.Profunctor
+  -- other-modules:       
+  -- other-extensions:    
+  build-depends:       base >=4.9 && <4.12
+                     , transformers >=0.4.2 && <0.6
+  -- hs-source-dirs:      
+  default-language:    Haskell2010
+  default-extensions:  StandaloneDeriving
+                     , GeneralizedNewtypeDeriving