diff --git a/Main.hs b/Main.hs
index 4912fcf..79dcea6 100644
--- a/Main.hs
+++ b/Main.hs
@@ -24,6 +24,7 @@ import System.IO
 import Numeric (showFFloat)
 
 
+-- The Cambridge Haskell Supercompiler (CHSC)
 main :: IO ()
 main = do
     (_flags, args) <- fmap (partition ("-" `isPrefixOf`)) getArgs
diff --git a/README b/README
new file mode 100644
index 0000000..06b9ca6
--- /dev/null
+++ b/README
@@ -0,0 +1,61 @@
+The Cambridge Haskell Supercompiler (CHSC)
+===
+
+Overview
+---
+
+The Cambridge Haskell Supercompiler (CHSC) is a preprocessor which supercompiles programs written in a subset of Haskell. The output is
+source code suitable for presentation to the Glasgow Haskell Compiler (GHC) for compilation as standard Haskell.
+
+The hope is that the process of supercompiling the input makes it more efficient and hence CHSC can be used as a program optimisation
+tool. Because of the focus on program optimisation the design of CHSC is somewhat different from that of supercompilers used for
+theorem proving:
+
+  * We are careful to never duplicate work that is shared in the input program
+  * We compile a language which models full Haskell: in particular, we can supercompile strict primops and recursive let bindings
+  * We care a lot about code duplication and compile time, even if we don't have any good answers yet
+
+The intention is to eventually integrate the supercompiler into GHC to supercompile the Core language. This will let us truly supercompile
+any Haskell program, not just those written in the subset that CHSC knows how to desugar.
+
+Bugs
+---
+
+At the time of writing, there are no known bugs in the `master` branch of the supercompiler. However, supercompiling certain programs
+(even some of the examples I have provided) has never been observed to terminate due to the supercompilation code explosion problem.
+
+Using
+---
+
+If you want to try out the CHSC, use the `test` script:
+
+    $ ./test examples/toys/MapMapFusion.core
+
+This will print output similar to the following:
+
+    examples/toys/MapMapFusion.core
+    mapmapfusion & 0.0s & 0.50 & 0.82 & 1.02 \\
+
+The fields on the second row are, from left to right:
+
+  1. The name of the benchmark
+  2. The time taken to supercompile (in seconds)
+  3. Time taken by GHC to compile to the supercompiled program, as a fraction of the time taken for the input program
+  4. Runtime of the supercompiled program, as a fraction of that of the input program
+  5. Total heap allocation by the supercompiled program as a fraction of that of the input
+
+In addition to supercompiling and running the benchmarks, the test script outputs the supercompiled forms of the programs:
+
+  * The input program (as a valid Haskell program) is placed in `input/examples/toys/MapMapFusion.hs`
+  * The output program (again, as valid Haskell) is placed in `output/primops/gen/examples/toys/MapMapFusion.hs`
+
+Naturally, the suffix of this file name varies with the file name that `test` was invoked with.
+
+You can use `test` with more than one filename if you would like.
+
+Paper
+---
+
+A description of the design of CHSC was accepted to the Haskell Symposium 2010, and is available online:
+
+  * [Supercompilation by Evaluation](http://www.cl.cam.ac.uk/~mb566/papers/sbe-hs10.pdf)