I can't speak to how easy this book is to digest for a beginner, but "comprehensive" is definitely the correct description. Having a reference and a learning guide in one book is incredibly useful; you can look up a function to refresh your memory on the argument list, or read the section on a topic to figure out how to approach a problem in the first place. I like it better than the Red Book, and having one or the other is a must for an OpenGL programmer.