I don't know about buying them all but eight or nine manuals would be just fine - oh, keep them up to date every few years too.

WileyWapiti

I believe you should have at least the Reloading Guide from the Bullet & the Powder Manufacturer you are using. The more books you get and read the better perspective you get…. Some are a tad pricy, but on the good side they are current for a couple of years. Don’t use backdated books as your source of data… unless you check it against a current edition… things change.

It's interesting that no one has mentioned the Barnes reloading manual among their favorites. It was mentioned as an example of one with an error in an earlier printing - which is quite true but I suspect is true of many of the other manuals too.

I do use a Barnes reloading manual mostly because I like Barnes bullets. I also use the Sierra book a lot and have a couple of others. One that I turn to once in a while is a 20+ year old copy of "metallic cartridge reloading." This book was published before all of the component manufacturers started publishing their own. It was also before the max loads were reduced by lawyers or better pressure measurements as some will contend.

I have that one...Metalic Cartridge Reloading...Mine is a 1982 edition and cost $10.95 back then. Some of the loads are a little high and, believe it or not, some of them are a little low, too....

All of the books sugested so far are good examples of reloading manuals. The best book I have read on loading is Glen Zedikers book "Handloading for Competition". I have had this book for four years and have read and reread it 6 or 7 times. Not only is easy to read but lets you understand loading from all angles and lets you decide how good you want your ammo to be.

Bob

I prefer to have the manual of the bullet I'm using, and the powder I'm using. (I like manuals)
P O Ackley's Handbook For Shooter and reloaders is a fascinating book(s), but I would caution you against using the loading data in it- the data in it is 40 years old, and was never tested by Ackley- he printed whatever the wildcat designer suggested...and before the days of chronographs and pressure test equipment, some of those guys were really on the edge. Some load data I look at in Ackleys book is downright scary.
A book I think is a must for anyone that loads a number of calibers, or would like to, is Ken Waters' book Pet Loads. It's available from Wolfe Publishing.

If you ever load Barnes Blue XLC's you will need a Barnes # 3 manual.

Speer #13 I use a lot, and Hodgdon's, too .