The course is devoted to creation of 64-bit applications in C/C++ language and is intended for the Windows developers who use Visual Studio 2005/2008/2010 environment. Developers working with other 64-bit operating systems will learn much interesting as well. The course will consider all the steps of creating a new safe 64-bit application or migrating the existing 32-bit code to a 64-bit system. The course is composed of 28 lessons devoted to introduction to 64-bit systems, issues of building 64-bit applications, methods of searching errors specific to 64-bit code and code optimization. Such questions are also considered as estimate of the cost of moving to 64-bit systems and rationality of this move.