Review: „Learning Ruby” By Michael Fitzgerald, O’Reilly Media
This book is good introduction to the Ruby language for beginners. Book covers the most important aspects of language: syntax, data structures, classes, some common libraries, etc. Reader need to be aware that book was published in 2007 and there are outdated parts (e.g. there are newer versions of Ruby and Ruby on Rails).
Learning Ruby can be still valuable position for beginner however I would recommend find more up-to-date book.
Product page: http://shop.oreilly.com/product/9780596529864.do