Ruby is a relatively new object-oriented language, developed by Yukihiro Matsumoto in 1995 and borrowing some features from the languages LISP, Smalltalk, Perl, CLU and others. The language is actively developing and is used in a variety of areas: from system administration to the development of complex dynamic websites. The book is a complete guide to Ruby - it can be used as a textbook, as a reference book, and as a collection of answers to questions like “how to do this or that.” in Ruby." It contains over 400 examples, divided into various aspects of programming, and to which the author provides detailed comments. The publication is intended for programmers of a wide range and very different qualifications who want to learn how to work efficiently and professionally in Ruby.