I used to have two. BBQ bible ( which I gave to my Son ) and Smoke & Spice ( which I gave to a member on the old forum who was stationed over seas in Iraq )
I liked both, but my favorite cookbook is JOY. It simply lays out a recipe by ingredient ( step by step ) and tells you the why's and why not's on cooking certain foods.
A WSM or Weber kettle is just a charcoal fired oven, and most recipes cooked indoors can be done outdoors with a little thought and planning.
And both give you that little sumpin, sumpin you don't get cooking on an indoor appliance.
Tim