I second the motion on Raichlen's books (especially "How to Grill" for grilling). Just finished reading that fantastic meat book, The Complete Meat Cookbook by Bruce Aidells and Denis Kelly (perfect if you want to learn which steaks come from where on the steer), and Robb Walsh's "Legends of Texas Barbecue." Both were fascinating.
I'd also recommend that Barbecuing & Sausage-Making Secrets by Charlie and Ruthie Knote (out of print, but you can find it----I think I got mine at Barnes and Noble.com for $15, since Amazon's used ones were going for $90).
Lastly, I can't recommend these old books I got off of ebay, but I'll name them cuz they tickle me: Jim Beard's Complete Book of Barbecue & Rotisserie Cooking (1954---and it's THE James Beard, btw). Sunset Barbecue Cookbook (1957). The Master Chef's OUtdoor Grill Cookbook (Culinary Arts Institute, 1963). The American Illustrated Cook Book of Barbecues (1972). Better Homes and Gardens Barbecues and Picnics (1963). Gourmet International's Barbecue Cookbook (The Fine Art of Outdoor Cooking---1972). Sunset Barbecue Cookbook (1950).