The book is a guide to creating Ruby web applications. The study is based on practical examples, the listings of which are on almost every page. The basics of Ruby are given, conditional operators, strings and regular expressions, operators, functions, arrays, hashes, working with files, classes are considered. XML processing, reflection, metaprogramming, exception handling, Tk developer tools and other tools including RubyGems, RDoc and Embedded Ruby are described. Each chapter concludes with a list of questions on the topic. At the end of the book, for convenience, reference materials on the Ruby language are collected and answers to the test questions for the chapters are given. For web developers.