This book contains 14 chapters that guide you through PS5. The chapters are easy to follow and come with a CD of the sample images needed to complete the lessons. You can work your way through the book chapter by chapter or pick and choose a topic. I found doing the first 4-5 chapters gave me a good understanding of some basics and then I went on to do other chapters that had a higher interest for me. CS5 is a massive program so this book is not about to make you an expert. However, it does give you a start and shows you what can be done with the program. I have found it and the book by Scott Kelby on CS5 for Digital Photographers to be a sound investment as I try and become more familiar with Photoshop.
I'm sure there are more exciting or well-written books on Photoshop...and I've bought or plan to buy some of them...but I've had the official Adobe "Classroom In A Book" series for every version as I've upgraded, and they're unfailingly solid tutorials. This book, like the others, covers all the basics and points you in the direction of supplemental online material. It's a good starting point for tackling version changes and learning new tools.