I've read all of the usual suspects regarding autobiographies, and consider the holy trinity to be Foley's 1st book, Jericho's, and Bret's.
I have read some books written about the business by non-wrestlers (Sex, Lies, and Headlocks was bad; Broken Harts was decent; etc.), but the biggest task of that group was National Wrestling Alliance: The Untold Story of the Monopoly That Strangled Pro Wrestling by Tim Hornbaker.
First things first: the book is dry. There are colorful spots where certain promoters or wrestlers are quoted, but the majority of the information is given in Hemingway-like ham-fisted typing tone, with no real emotion attached, unless they use one of the aforementioned quotes.
However, that's really the primary flaw. I can't speak for the accuracy of every statement or tidbit, but it seems like research was actually done. However, I could be incorrect; I am not an expert on pre-70s NWA, so there could be tons of mistakes. Regardless, it doesn't seem that this is the case.
The section where each NWA champion is profiled is interesting, although there are many that get minimal coverage for various reasons (short reign, lack of popularity, etc.). I am also very interested in the origins of the NWA and the business itself at that time (and before), so I found a lot of the discussion of people like Orville Brown interesting. There is a lot of talk about the political maneuverings of the various promoters, which is to be expected, but after so many double crosses/feuds, they all start blending together after a while.
The point is that I would recommend the book if you're interested in the formation/early years of the NWA. Again, it's dry, but I can overlook that for what else the book contains, and there are many interesting bits within that help add to the overall "story" of the NWA.