GTK is accessible through several programming languages, such as C++, Guile, Perl,Python, TOM, Ada95, Objective C, Free Pascal, Eiffel, Java, and C#. This document covers Ruby/GTK2, the Ruby binding for the GTK library version 2. The reader should have some Ruby knowledge. It would be better if he/she has some experience on X programming, but this is not required.This document is still under construction. Do not hesitate to send comments or as questions to the mailing list. Any feedback will be greatly appreciated.