diff --git a/src/README.md b/src/README.md
index 272f9b81d..7bfd4a1ba 100644
--- a/src/README.md
+++ b/src/README.md
@@ -1,5 +1,41 @@
-# ASEPRITE Source Code
+# Aseprite Source Code
 
-If you are here is because you want to learn about ASEPRITE source
+If you are here is because you want to learn about Aseprite source
 code. I'll try to write in these `README.md` files a summary of each
 module/library.
+
+# Modules & Libraries
+
+Aseprite is separated in the following layers/modules:
+
+## Level 0: Completely independent modules
+
+These libraries are easy to be used and embedded in other software
+because they don't depend on any other component.
+
+  * [allegro](allegro/): Modified version of [Allegro](http://alleg.sourceforge.net/) library, used for keyboard/mouse input, and drawing 2D graphics on screen.
+  * [base](base/): Core/basic stuff, multithreading, utf8, sha1, file system, memory, etc.
+  * [gfx](gfx/): Abstract graphics structures like point, size, rectangle, region, color, etc.
+  * [scripting](scripting/): JavaScript engine ([V8](https://code.google.com/p/v8/)).
+  * [undo](undo/): Generic library to manage undo history of undoable actions.
+
+## Level 1
+
+  * [net](net/) -> base: Networking library to send HTTP requests.
+  * [raster](raster/) -> base, gfx: Library to handle graphics entities like sprites, images, frames.
+  * [she](she/) -> allegro: A (Work In Progress) wrapper for Allegro library.
+  * [webserver](webserver/) -> base: HTTP web server (based on [mongoose](https://github.com/valenok/mongoose))
+
+## Level 2
+
+  * [filters](filters/) -> base, gfx, raster: FX for raster images.
+  * [ui](ui/) -> base, gfx, she: Portable UI library (buttons, windows, text fields, etc.)
+  * [updater](updater/) -> base, net: Component to check for updates.
+
+## Level 3
+
+  * [app](app/) -> allegro, base, filters, gfx, raster, scripting, she, ui, undo, updater, webserver
+
+## Level 4
+
+  * [main](main/) -> app, base, she, ui