The book describes the basics of the architecture of the .NET platform and the intermediate language of this platform - Common Intermediate Language (CIL). A programming technique called dynamic code generation is discussed in detail. An introduction to multitasking is given and approaches to developing parallel applications based on the .NET platform are described. Addressed to all students of the creation of meta-tools and the development of compilers for various operating systems. For students and teachers of universities, as well as for specialists who improve their qualifications.