Linux device drivers / Jonathan Corbet, Alessandro Rubini, and Greg Kroah-Hartman, O’Reilly, 2005
If you are doing some kernel programming, this book is one of your most important resources. They joke that this book is easier to read than the code, implying that the book is almost as hard to read as the code. But you will want to read the code, because the rules for driver design change often. The authors are in the kernel inner circle.