Cthulhu Mythos – Le Mythe de Cthulhu par Sandy Petersen

Sandy Petersena s Cthulhu Mythos is the most comprehensive guide to including Lovecraftian elements in your Roleplaying game, written by the author of the groundbreaking Call of Cthulhu role-playing game, and developed primarily by James Jacobs (creative director of Paizo) and David N. Ross.