Kernel development can be a daunting task and is very different from programming traditional user applications. The kernel environment is more volatile and complex. Extraordinary care must be taken to ensure that kernel code is free of bugs because any issue may have serious consequences to the stability, security, and performance of the system. This book covers the fundamentals necessary to begin programming in the kernel. We cover kernel development from a theoretical and practical point of view. We cover concepts fundamental to kernel development such as virtual memory and synchronization, as well as more practical knowledge. The book primarily focuses on Mac OS X, however.