Back in the early days of Twelve Step before the existence of the Big Book, Bill Wilson in conferring with Dr Bob Smith (the co-founders of the 12 Step movement) both noticed, as this program was passed by word of mouth, it began to distort. Four or five generations of being passed one alcoholic to another, it started to get off track. In Akron some religious ideas were starting to trickle into their practices. In New York some psycho-therapeutic ideas began to infiltrate the program. And while both of these institutions are noble and well meaning, they are not Twelve Step. Their goals and methods are not the same as those of the Twelve Step Program. 

Bill and Dr. Bob together contrived an idea to have a book written that would document what the Twelve Step Program was. While they introduced several other ideas to the Fellowship, this is the one that was approved. Bill Wilson set out to then document the actions common to the overall Fellowship. The actions they believed brought about removal of their obsession. While Bill Wilson wrote the book, his role was merely one of documentation, not author. Bill would write portions of the book and submit them to the groups existing at that time. The Fellowship would review the book and inform Bill where he was on track and where he was completely off base. (“Pass It On: Bill W. and How the A.A. Message Reached the World” p. 190)

So the true authors of the book are those early pioneers of the Twelve Step Program.