Olivier Langlois's blog

This book is considered as the windows programming bible by many. Sure, you can build applications without all this knowledge with frameworks such as MFC but if you are looking to build a Windows program that do exactly what you want, there is no workaround a deep Win32 API knowledge. This book is a must for all Windows programmers bookshelf.

Something you need to know before purchasing this book is that it is very unlikely that the author will update this gem one more time as Microsoft is slowly phasing out the Win32 API in favor of the .NET framework and this will be even more real when Vista comes out. However, since there is a huge codebase of existing Win32 programs, the Win32 API will certainly stay around for a long long time. This book is simply the best for learning Win32 programming. I still refer to it very frequently. If you are looking for a reference book on Win32 API, this is the one you were looking for.