diff --git a/README.md b/README.md
index 0404cd2..cae396a 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,36 @@
 Jiffy - JSON NIFs for Erlang
 ============================
 
-I wrote a JSON parser. Lets see how fast it is.
+A JSON parser as a NIF. This is a complete rewrite of the work I did
+in EEP0018 that was based on Yajl. This new version is a hand crafted
+state machine that does its best to be as quick and efficient as
+possible while not placing any constraints on the parsed JSON.
+
+Usage
+-----
+
+Jiffy's API is a drop in replacement for the EEP0018 application. The
+JSON representation in Erlang is also exactly the same.
+
+    Eshell V5.8.2  (abort with ^G)
+    1> jiffy:decode(<<"{\"foo\": \"bar\"}">>).
+    {ok,{[{<<"foo">>,<<"bar">>}]}}
+    2> Doc = {[{foo, [<<"bing">>, 2.3, true]}]}.
+    {[{foo,[<<"bing">>,2.3,true]}]}
+    3> jiffy:encode(Doc).
+    {ok,<<"{\"foo\":[\"bing\",2.2999999999999998224,true]}">>}
+
+
+Data Format
+-----------
+
+    JSON             ->   Erlang
+    null             ->   null
+    true             ->   true
+    false            ->   false
+    1                ->   1
+    1.25             ->   1.25
+    []               ->   []
+    [true, 1.0]      ->   [true, 1.0]
+    {}               ->   {[]}
+    {"foo": "bar"}   ->   {[{<<"foo">>, <<"bar">>}]}