The first edition of the Ars Mysteria (If you have a copy, hold on to it! It’s a major collectable. Contact me, and I can set you up with someone who’ll pay you big time for it!) – the first edition was compiled by Simon Magus in the second century CE. He was THE wizard of his time, and he compiled everything he had managed to uncover about ancient Sumerian and Egyptian magic, along with a bit of Greek stuff, mostly how to make and use orichalcum, the first magic metal.
In the seventh century Merlin Sinestra (yes, THAT Merlin!) added several chapters of his own on Druidic magic and pre-Viking runes. Twelfth century rolls along, and an unknown wizard in the court/army of Bela IV of Hungary captures the stash of a Mongol shaman in Batu’s invading army after it was pushed out of Hungary. Said wizard then bought a literate Chinese POW captured during the battle, taught her Hungarian, and got her to read the scrolls to him.
When the printing press arrived, the third edition, which was the first printed one, contained the translated Chinese texts. The fourth, and final, 19th century edition was translated, edited, and annotated by the Compt de Saint Germain, who was either an immortal alchemist or a vampire mage, depending on who you talk to. He added his own notes on alchemy, and a ton of stuff from someone he identified only as “Haggard”.
“Haggard” was apparently one of the first of the Pith Helmet and Khaki Pants brigade who spent their lives discovering places where people had lived for centuries. He made copious notes, however, wherever he went, and a lot of what we know about African and Asian magic came from them. His contributions added four chapters and expanded three more.
In a way, it was the printing press that doomed the Ars Mysteria. Too many people now had access to its contents, and spellhammers were overworked for most of the century dealing with the curses, demons, plagues, and incursions brought about by idiots that couldn’t or wouldn’t learn how to pronounce myrfyddyn cryff. The book was actively hunted down and locked away in library vaults, and students who had until then learned from the Ars Mysteria now learned from the Concordance of Magic. The difference between the two is that The Concordance will tell you demons can be summoned using magic circles, while the Ars has diagrams, and instructions showing you how to draw the circles, and includes the words to several summoning rituals. The Concordance requires an instructor to learn from it. The Ars allows you to learn on your own.