Chaosium, (Kay-Oss-Eum) is known for publishing high quality books & games, and for having a well-developed sense of fun.

In 1975 the company was founded as The Chaosium by Greg Stafford. It was later incorporated as Chaosium Inc. Chaosium thrives in the mild climate, gorgeous surroundings, and gentle earthquakes of the San Francisco Bay area. The company has entered the 21st century and gone virtual, closing it's California office.

Most of Chaosium's product lines are based upon literary sources. H.P. Lovecraft's 1920's horror fiction provides the basis of the classic Call of Cthulhu roleplaying game line which has won so many awards that the we have lost count, though we do know that there are more than 70 of them. Mr. Lovecraft also provides the inspiration for our many Call of Cthulhu Fiction collections.

In 2015, Chaosium is celebrated our 40th anniversary. In 2011, Call of Cthulhu celebrated it’s 30th anniversary.

Chaosium strives to educate players and readers, as well as entertain them. Our games emphasize the spirit of companionship and camaraderie, as the players' characters struggle against villains and evil-doers presented in adventures. Though our game worlds may be magical or horrifying in nature, we feel teenagers and adults can learn valuable lessons through roleplaying our games.

We strongly believe in quality design and literary excellence. Chaosium Inc. is renowned in gaming circles for the crisp appearance of our game books, our high word counts, and value. Our rules system, the Basic Roleplaying System of BRP is well thought out and was the first to use skills based upon the d100 mechanic. Call of Cthulhu and RuneQuest use BRP as their basis of their rules. Once you've learned to play one of our games, you've learned to play them all.

We keep our games entertaining above all things. After all, we are in the business of entertaining you.

We also see it is our duty to help keep Lovecraft's legacy alive. Our Call of Cthulhu Fiction line seeks to reprint classic tales, often long out of print and nigh-impossible to find otherwise, as well as bring you the best of today's Cthulhu Mythos fiction.