Call of Cthulhu is a horror fiction role-playing game based on H. P. Lovecraft's story of the same name and the associated Cthulhu Mythos. The game, often abbreviated as CoC, is published by Chaosium. The game was first released in 1981, and eighteen editions (mostly fairly minor revisions) have been published to date. The game makes use of Chaosium's Basic Role-Playing (BRP) system, first seen in the game RuneQuest, but with special rules for Sanity. It is notable among roleplaying games for its longevity and also for remaining largely unchanged for most of its history, with only the most recent seventh edition making significant changes to the rules.