This book seems to offer a quick rundown through *nix operating systems for the absolute beginners. I'm not quite sure why I picked up this book, as I have been playing around with *nix for a couple of years now.. I was able to learn a new trick or two by reading this between classes earlier today, and would not recommend it -- as other reviewers pointed out, there's better stuff out in the wild. One thing that comes to my mind is Zed Shaw's book on this topic.