Since the introduction of Mac OS X which comes with Darwin (a flavour of an Unix variant, FreeBSD), I have bought several books in order to get familiar with Unix and to start using popular open source applications such as MySQL and PHP. Some of these books dealt with Unix in general, some have been written for Mac users like myself.
With Matisse Enzer's help, I have finally achieved my goal and I know now not only how to start the Apache server which comes standard with Mac OS X but also how to change my configuration so this happens automatically every time I restart the machine.
The book is written in a very clear style with a dry sense of humour, loads of useful tips and interesting background information in sidebars. The first 20 pages already taught me more than other books hadn't been able to show me in their entirety. The reader is being addressed by the writer as an intelligent person, not as a dummy. The book is packed with practical bits I could start to use immediately (simple scripts, the power of pipelines, for instance).
If you are running Mac OS X and would like to use the force of Unix (for example, by turning your machine into a server with a web-ended, PHP scripted MySQL database), but always had trouble getting a handle on Unix, this book is the one (and maybe only) you need. It will take a while before a book on Unix will come along for Mac users that surpasses Matisse Enzer's "UNIX for Mac OS X".
Matisse, chapeau!