This is an exceptionally useful book that does just what it says: it teaches Apple Macintosh OS X users how to use the Terminal application (which comes as part of the new operating system), and then how to use the version of UNIX that comes with it. It provides one of the best, most readable introductions to UNIX that I've come across, so if you want to learn UNIX from scratch, you might find this book useful even if you don't use a Mac. My only complaints are (a) I'd like the book to be longer - this is a measure of how good it is; (b) I'd have liked more on what you could do with UNIX on your Mac. But still, it's an excellent introduction. I read it like a novel, but now refer to it frequently.