There are three things that you have to know about Scott Kelby: i) he is possibly the most knowledgeable person about Photoshop on the face of the planet; ii) he has a rare ability to explain complex processes clearly, backed up by illustrations which are large and actually helpful; and iii) the man is as mad as a hatter.
Once you accept the fact that parts of this book will wander into a world largely populated by Monty Python, you will find that this is the one book that you absolutely have to have, if you are going to use Photoshop CS5 both effectively and enjoyably.
Each step is described with such crystal clarity that even someone as technically inept as myself can quickly grasp both the principle and the practice of the various techniques to take your photographs from RAW to a final state that reflects exactly where you want to go with the image.
There are times when I get the feeling that Scott Kelby actually knows more about Photoshop than the Adobe wizards who created it in the first place.
If you are a CS5 user, the bottom line about this book is this: just buy it.