Well, Fook pretty much covered everything, except the rule book. That's the "CAMS Manual of Motorsport." It's a fairly lenghty tome that is updated yearly. It's about $60 to the great unwashed, but an easier way is to borrow last years one off me, and I always have a last years one, because the barstards make me buy a new one when I renew my Rally License. Not a great deal changes, and anything major, I'll be able to tell you anyway. It tells you everything. And you can't hold a decent argument at an event unless you a) have one, and b) know it. At club level though, it's not imperitive to have one, unless you're building a car to a particular class. Hope this helps.
R