Eloquent Ruby (en Inglés) - Russ Olsen;Michael Swaine

Write better, clearer, more focused Ruby code by becoming truly fluent in the language. 

As a Ruby programmer, you know how powerful and expressive it is. But do you really know how to make the most of that power, and how to use it to express your ideas succinctly and clearly. Do you know how to metaprogram; to create code that expresses your problem domain? Do you use modern tools to check your style, and even to check your types? Do you know the four distin ct uses of Ruby blocks?

Ruby is an easy programming language to learn, but to gain the fluency needed to write great Ruby code, you need to break old habits. Start thinking about code the way experienced Ruby programmers do. Grok how they solve problems. Dig below the what to the why  of Ruby conventions. Thoroughly updated to reflect modern Ruby usage and with new chapters covering pattern matching and concurrency, Eloquent Ruby, Second Edition will help you take advantage of the power and flexibility of the Ruby programming language.