I love this book. It has milion of usefull tricks I never even knew I could do.

It is not meant for a complete newbie (although I was pretty close to one when I started using it), nor would I recommend it as a serious study book. It's more like a book that you would take to bed before going to sleep. The guy is really funny so it has a great entertainment value. However, anytime you read it you will learn about a new way to customize your shell or command line editing feature you never heard about or a new approach to understanding some concept you struggled with. It's kind of modular, just the way Unix is: bunch of little but life saving advices. You could tell that the guy worked with Unix for years. If I would have to describe it in three words, I would say: bag of tricks.

The book is slightly outdated as it is written in 1995 and I am not aware if there is a newer edition. But this is not much of an issue, cause the Unix has been around forever.