A Little Ruby, A Lot of Objects (Brian Marick)
The goal of this book is to teach you a way to think about computation, to show you how far you can take a simple idea: that all computation consists of sending messages to objects. Prerequisites is reader will know at least one programming language, not necessarily.
Author(s): Brian Marick
NA Pages 
I Love Ruby Get started with the greatest programming language made for humans
Ruby is an easy to learn programming language. This book describes the fundamental concepts and techniques in greater depth than traditional introductions.
Author(s): Karthikeyan A K
NA Pages
This book is the only Rails book that does test-driven development the entire time, an approach highly recommended by the experts but which has never been so clearly demonstrated before. Finally, by including Git, GitHub, and Heroku in the demo examples, the author really gives you a feel for what it’s like to do a real-world project. The tutorial’s code examples are not in isolation.
Author(s): Michael Hartl
NA Pages
