Mac OS X For Unix Geeks 4th Edition provides an overview of the "Leopard" (10.5) version of the Mac OS X operating system. It is divided into four sections covering day-to-day use, developing software for the Mac, dealing with various package management systems (ports, fink, etc), and using Mac OS X as a server. The first two sections are particularly good at providing an overview of their topics along with many references to online resources for further information. The package management section was interesting, but less illuminating as there is not really much to learn if you are familiar with the tools. The final section is the weakest in the book: you could probably write a whole book on how to run Mac OS as a serve and this section feels very rushed.

Books covering specific software packages suffer from two problems: pallid regurgitation or online reference material, and rapid obsolescence.

Mac OS X For Unix Geeks avoids the first problem by way of its unifying theme: what does Mac OS X look like to a UNIX geek? The authors do a very good job of relating how Mac OS X differs from other UNIX variants in both technical detail (for example, differences in handling dynamic libraries) and in user workflows (for example, using the Terminal to fire off an SSH connection over Bonjour rather than just using ssh).

There is not too much that an author can do regarding obsolescence. Already a new version of Mac OS X is available (Snow Leopard). However many of the topic in this book will be relatively stable with that release and so this book is still worth a look at least until O'Reilly comes up with a new edition. ( )