This book assumes that the reader is already familiar with the subject matter. Using many code samples it focuses on "how-to use Ruby" for specific applications, either as a stand-alone language, or in conjunction with other languages. It covers simple data tasks, manipulating structured data, external data manipulation, user interfaces, handling threads, system programming, network and Web programming, and tools and utilities. The appendices offer instruction on migrating from Perl and Python to Ruby, and extending Ruby in C and C++