Carl,
I am in the early stages of building my first rifle. Prior to starting (in fact, prior to ordering the kit), I purchased, read and studied Alexander's "Gunsmith of Grenville County", Shumway's "Recreating the American Longrifle" and Dixon's "The Art of Building the Pennsylvania Longrifle".
All three were extremely helpful in in my starting-from-zero education. However, now that I'm actually doing the work, I find myself referring more frequently to Dixon's book. The explanations and sequence of tasks are easier to follow and make more sense to me. For example, Alexander and Shumway don't pin the barrel in until after a number of other steps; Dixon does that right away. I'm sure this is a personal preference type of thing but, I'd rather pin the barrel in before positioning the lock, etc.
My other recommendation is to go through the old Gun Building posts, either using the search function or just trolling for relevant topics.
Have fun,
Bill