This is the fourth edition of the main book on the C# language, written by programming legend Anders Hejlsberg, architect of C#, Delphi and Turbo Pascal, together with other specialists who were part of the C# development team at Microsoft. The publication is the most complete description of the language and the most authoritative source of information on this topic, built in the format of a collection of specifications, including a description of the syntax, supporting materials and examples, as well as code samples. This book is a developer's bible that can easily replace both MSDN and other C# books. The fourth edition covers new features in C# 4.0, including dynamic binding, named and optional parameters, and covariant and contravariant generic types. . The goal of these innovations is to enhance C#'s ability to interact with objects outside of the .NET platform. A distinctive feature of the new edition is also that each chapter of the book contains extensive comments written by famous programming gurus such as Jon Skeet, Joseph Albahari, Bill Wagner, Christian Nagel, Eric Lippert, etc.