Documentation

Here you will find pointers to manuals, tutorials, and reference material that will come in handy when you feel like coding in Ruby.

Try Ruby!: An interactive tutorial that lets you try out Ruby right in your browser, courtesy of Why the Lucky Stiff. No installation required!
Ruby in Twenty Minutes: A brief tutorial covering the basics of Ruby. From start to finish it should take you no more than twenty minutes.
Ruby from Other Languages: Coming to Ruby from another language? Whether it's C, C++, Java, Perl, PHP, or Python, this article has you covered!

Programming Ruby: The seminal work on Ruby in English, this first edition of the Pragmatic Programmers' book is available for free online.
Why's (Poignant) Guide to Ruby: An off-the-wall introduction to Ruby that teaches the language through stories, jokes, and comics. Originally created by Why the Lucky Stiff.
Ruby User's Guide: Translated from the Japanese version originally written by Yukihiro Matsumoto (the creator of Ruby), this guide gives an overview of many aspects of Ruby.

Ruby Core Reference: Pulled straight from the source code using RDoc, this reference work documents all of the core classes and modules.
Ruby Standard Library Reference: Also pulled from the source code using RDoc, this reference work documents the standard library.
Ruby C API Reference: Documentation of Ruby's underlying C code. Great if you want to write C extensions or contribute to Ruby's development.