I agree with Rick, "the two Volume Parker Story is heads and shoulders above all other books" on Parker Bros. shotguns. The
Larry Baer and Ed Muderlak book order are interchangeable and lastly the Peter Johnson book. BUT, the order is irrelevant because I recommend owning and reading all of them if you have an interest in Parker Bros.
For those who want a list of these books and a short description of each, this can be found in our FAQ answer page at http://parkerguns.org/pages/faq/learn.htm