This book is a frame by frame, widget by widget, menu item by menu item prescription for "proper" Windows application etiquette. By following this book's advice, your applications will look and feel just like a member of Microsoft Office. You'll learn everything from how many units to space a button from the border of a box to how to select multiple discontinuous pieces of text and then copy and paste them across applications. There's even instructions on editing the registry so that your documents can be printed from the explorer.
It's essentially a style guide for Windows GUIs the way the Chicago Manual of Style is a style guide for writing English. It won't make you a good writer, but no one will correct your punctuation.
I actually found this book useful from a Windows user perspective. It tells you how all the controls are supposed to work. If you use MS apps a lot, you've probably intuited a lot of this, but it's interesting to see it all laid out.
This book does not explain how to use the Windows APIs to create GUIs. Get a book on Visual C++ or VB for that. This book does not explain how to design a usable application. Read Jeff Johnson's GUI Bloopers or Alan Cooper's About Face. This book does not teach you to be a visual designer.
This book is about as interesting to read as a typical user's manual. It's one unforgiving piece of advice and description after the next without a single case study in the entire 500+ pages.
Even so, if you want to understand how Windows apps are "supposed" to behave or you have to write such applications yourself, this book is a must-have.