This book is a detailed description of the internal structure and functioning of the Microsoft .NET Framework Common Language Runtime (CLR) version 2.0. It discloses the .NET Framework type system and explains how to manage them. Introduced programming concepts with extensive use of the FCL library that apply to all languages ​ ​ focused on working with the .NET Framework. Particular attention is paid to generalizations, management of asynchronous operations and thread synchronization. The book is aimed at developers of any kind of applications on the platform with the .NET Framework: Windows Forms, Web Forms, Web services, console applications, etc. The book consists of 24 chapters.