This book can't offer the kind of detail, tricks, and hidden features found in the newer, specialized books on Win32. Most of those books are written from the point of view of a C-language programmer: in order to use them, you'll have to understand the underlying Win32 API and its relationship to the MFC library. In addition, you'll need to know about the Windows message dispatch mechanism and the role of window classes.
This book's "For Win32 Programmers" sidebars, scattered throughout the text, help you make the connection to low-level programming for Windows. These specially formatted boxes help experienced C programmers relate new MFC library concepts to principles they're already familiar with. If you're unfamiliar with low-level programming, you should skip these notes the first time through, but you should read them on your second pass through the book. Even though you may never write a low-level Windows-based program with a WinMain function, for example, you eventually need to know how the Windows operating system interacts with your program.