Books or Info about Mac OS X under the hood Can somebody point me in the direction of books, sites, articles, ... to learn everything about Mac OS X "under the hood"? In other words to learn more about the kernel, the system.

ps.: About Snow Leopard of course
I've read several articles by Amit Singh at http://kernelthread.com, and have always found them very interesting.

He's book is Mac OS X Internals: A Systems Approach