Options. In an RPG, you can never have enough options, if you ask me. And The Book of Many Things gives both players and GMs just that, options. Lots, and lots, and lots of options, for just about everything. The print version of the Pathfinder version of the book is up on Kickstarter now.
From the campaign:
Thrill at the fascinating, the bizarre, the deadly. Try your hand at powers unlike any before. Become what you want. The Book of Many Things by Samurai Sheepdog is a collection of player options for the Pathfinder® Roleplaying Game. Inside each volume is a compilation of requests from around the world, written out and made playable for you.
The campaign is well beyond its funding goal with still 10 days left to go.