This book is devoted to the development of applications using the application programming interface of Microsoft operating systems (Windows 9x, Windows XP, Windows 2000 and Windows Server 2003). The focus is on core system services, including file system, process and thread management, inter-process communication, network programming, and synchronization. The technique of transferring applications written in the Win32 environment to the Win64 environment is considered. All aspects of Windows security and its practical application are described in detail. The abundance of real examples, also available on the book’s website, greatly simplifies the learning of the material. The book is aimed at developers and programmers, both highly qualified and beginners, and will also be useful for students of relevant specialties.