1. Programming Ruby (2nd Edition)
By Dave Thomas & others — a comprehensive guide to Ruby language basics and beyond.
View PDF2. The Little Book of Ruby
By Huw Collingbourne — beginner-friendly guide to Ruby fundamentals.
View PDF3. The Book of Ruby: A Hands-On Guide
By Huw Collingbourne — hands-on exploration of Ruby programming.
View PDF4. Ruby Programming (Wikibooks PDF)
WikiBook edition — free PDF for Ruby language theory and practice.
View PDF