I have no idea how to publish a book but I have thought of a book about the most used caliber for allround use during the british empire.
I know Cal Pappas also mentioned it one time.

I know it will take time, but I am a bit thrilled with the thought. Vintage .500cal stuff like bulletmolds, fixers, reloading tools etc ought to be illustrated. Old casedrawings, bulletdrawing etc should be added. Old catalogs from WR, H&H, Eley`s, Kynochs that portraits a .500 express can be of use.

Experiences from the litterature of the period could be quoted in regards to use of the .500ex.

Basically a book where one will find just about everything one need to know about the caliber regardless if one is a cartridge collector, blackpowdershooter, hunter with vintage firearms,reloader or perhaps guncollector. Sort of a compendium.