The Ruby Programming Language

The Ruby Programming Language is the authoritative guide to Ruby and provides comprehensive coverage of versions 1.8 and 1.9 of the language. It was written (and illustrated!) by an all-star team:

David Flanagan, bestselling author of programming language "bibles" (including JavaScript: The Definitive Guide and Java in a Nutshell) and committer to the Ruby Subversion repository.

Yukihiro "Matz" Matsumoto, creator, designer and lead developer of Ruby and author of Ruby in a Nutshell, which has been expanded revised and to become this book.

why the lucky stiff, artist and Ruby programmer extraordinaire.
This book begins with a quick-start tutorial to the language, and then explains the language in detail from the bottom up: from lexical and syntactic structure to datatypes to expressions and statements and on through methods, blocks, lambdas, closures, classes and modules.