Underneath the colorful interface of Mac OS X is a powerful, complicated operating system based on BSD Unix. And Mac users of all kinds continue to need help both in figuring out how to run OS X and in understanding how OS X works underneath the covers and how to get the most out of it. In 2005 Apple is expected to release a new version of OS X-code-named "Tiger"-that will add some performance and interface enhancements, and that will further extend the capabilities of the underlying Unix-based subsystem. The fourth edition of Mac OS X Unleashed takes the same approach as the best-selling first three editions, helping the reader deal with the most trouble-prone aspects of the user interface-including the new features in the latest version-but focusing to a much greater extent on the BSD environment and how the user or administrator can get the most out of both the current operating system as well as the new components expected in the latest version.