This is what a good book should be like! It has a definite purpose, well written code and concise explanations.
The pretext of the book is that the author has already written a simple image viewer and now the authors are going to re-implement the software, but this time with a logical and systematic approach.
What is even better is that the code is platform independent (which is exactly as it should be) and extremely good code at that (all the code you need is supplied on the CD supplied with the book). It is well written, the process of how the original code could be re-written and improved upon is clear.
If you are a competent C++ programmer, you should seriously consider getting hold of this book, especially if your ultimate goal is clear code that can (with the minimal amount of effort) be recompiled on other platforms with the same results. I would not recommend it though if you are just setting out - it is seriously for advanced users. Highly recommended.