Grenville county is a good book. Alexander is an accomplished builder. His writing style is a bit different. I jokingly tell folks that The Gunsmith of Grenville County is written in Canadian.
I have to read and re read Alexander's writing as it is wordy. Sometimes less is more. In fairness to Alexander that book started out as a series of how too articles in Muzzleloader Magazine. He goes into to great depth to detail tasks that are very hard to describe.
What I find to be a great asset as a stand alone book and especially as a companion to Grenville County is Recreating the American Longrifle by Shumway, Buchelle and yes...Alexander. RTAL is written or at least edited in American.
I tend to understand RTAL better. If I want more depth I study Grenville. The pair together are really an asset to a new builder IMHO. Dixon's book is one that gives still another perspective.
No book no video no matter how good can make someone into a gunmaker. The only way is to do it either by hands on instruction or by trial and error. Even with hands on instruction...the student and future maker will develop their own way of doing things.
Does a car's Owner's Manual make one a driver? Does the shop manual for said car make one a mechanic?