There are several other books on programming for Mac OS X, but none of them comtain explanations of how to leverage the powerful underlying technologies. This book goes down to the real nitty-gritty of multi-threading, interprocess communication, networking, performance tuning, distributed objects, queues, Bonjour, authentication, the keychain, and directory services. The tools are also covered: gcc, gdb, subversion, Shark, and Saturn.