diff --git a/README.md b/README.md
index 66fac15..7e955bb 100644
--- a/README.md
+++ b/README.md
@@ -1,14 +1,49 @@
 # tartrazine
 
-TODO: Write a description here
+Tartrazine is a library to syntax-highlight code. It is 
+a port of [Pygments](https://pygments.org/) to
+[Crystal](https://crystal-lang.org/). Kind of.
+
+It's not currently usable unless what you need is a way
+to turn your files into a pile of json describing its
+constituent tokens, because I have not implemented any
+formatters, yet, only the part that parses the code (the lexers).
+
+TO make this even more "not there yet", Crystal doesn't allow
+for creating regular expressions that are MULTILINE but not
+DOT_ALL, whcih means I can't reproduce the behaviour of the
+golang (or Python's) regular expressions, so that causes
+issues unless you go and patch Crystal itself (don't patch Crystal itself, please)
+
+# A port of what? Why "kind of"?
+
+Because I did not read the Pygments code. And this is actually
+based on [Chroma](https://github.com/alecthomas/chroma) ... 
+although I did not read that code either.
+
+Chroma has taken most of the Pygments lexers and turned them into
+XML descriptions. What I did was take those XML files from Chroma
+and a pile of test cases from Pygments, and I slapped them together
+until the tests passed and my code produced the same output as
+Chroma. Think of it as *extreme TDD*.
+
+With a patched Crystal regex engine [see here](https://forum.crystal-lang.org/t/regex-that-is-multiline-but-not-dotall-how/7054)
+the pass rate for tests in the supported languages is 96.8%, which
+is *not bad for a couple days hacking*.
+
+This only covers the RegexLexers, which are the most common ones,
+but it means the supported languages are a subset of Chroma's, which 
+is a subset of Pygments'.
+
+Currently Tartrazine supports ... 241 languages.
 
 ## Installation
 
-TODO: Write installation instructions here
+If you need to ask how to install this, it's not ready for you yet.
 
 ## Usage
 
-TODO: Write usage instructions here
+If you need to ask how to use this, it's not ready for you yet.
 
 ## Development
 
@@ -16,7 +51,7 @@ TODO: Write development instructions here
 
 ## Contributing
 
-1. Fork it (<https://github.com/your-github-user/tartrazine/fork>)
+1. Fork it (<https://github.com/ralsina/tartrazine/fork>)
 2. Create your feature branch (`git checkout -b my-new-feature`)
 3. Commit your changes (`git commit -am 'Add some feature'`)
 4. Push to the branch (`git push origin my-new-feature`)
@@ -24,4 +59,4 @@ TODO: Write development instructions here
 
 ## Contributors
 
-- [Roberto Alsina](https://github.com/your-github-user) - creator and maintainer
+- [Roberto Alsina](https://github.com/ralsina) - creator and maintainer