I purchased this alongside the Illustrator Classroom in a Book course. What I found, as with any course, is that my experience was determined by my own effort. Adobe has done its part by developing a thoughtful series of lessons to make any user comfortable working in Photoshop.
I have heard two competing (and contrary) objections to these courses. People complain that there is a) either not enough or b) too much information in the Classroom in a Book series. It is true that Adobe has not developed a course that custom fits the requirements of every single possible user. This can hardly be held against them. They have created a series of straightforward courses for intermediate users. Neither this book (nor the application it is designed to teach) is for absolute beginners. It is for people who are comfortable in front of their computer. Nor should an expert user looking for some advanced tricks and tips purchase it. There are other books available to fit these needs.
Adobe Photoshop Classroom in a Book does a wonderful job orienting a typical computer user to a heavy hitting image manipulation application. If you take the time to complete this course, you will know your way around Photoshop. By properly learning the skills featured in this book, you will be prepared to absorb the sorts of tricks you have always wanted to learn.