Building drivers from scratch

[Josh Utter]

Greetings all,

Just opening the door to the Linux world, and since I'm doing so with a 
specific goal in mind (as opposed to just letting my curiosity carry me) 
I am hoping to get some direction.  I have device in mind that I'd like 
to build which would interface with my computer, so I'm wondering what 
books I might want to start with to learn how to make drivers from 
scratch (USB, but I'm not certain yet).  Any suggestions?

TIA

- josh