Lastly, I've noticed you've been asking some questions over the past
few days which are easily answered by a simple Google search - may I
suggest that as a first point of call in future. You'd probably learn
a lot more by searching for stuff yourself.
I'll second that. Google is probably the closest thing to Microsoft's Knowlege Base that Linux has for quick questions ;) .
There are a number of good books written on the kernel - Linux Device Drivers is due to have its third edition released in February. I'm glad - my second edition copy is starting to look a little ragged from constant reference.