Q: Copyrights and Trademarks - what are they?
A: Our intellectual property - our text and images - are legally protected by copyright, giving Chaosium/Moon Design Publications exclusive rights for its use and distribution. Our logos, titles and certain content are trademarks, which uniquely identify our products. For example, ‘Call of Cthulhu’ and ‘RuneQuest’, among others, are officially registered as Chaosium/Moon Design Publications trademarks, whereas the written text and artwork in these works are protected by copyright. How others (fans, small publishers, commercial licensees) get to use our copyrights and trademarks is through our Fan-Use and Licensing policies. If our copyrights are violated or trademarks are infringed - for example, someone producing an unauthorised Masks of Nyarlathotep graphic novel - and it comes to our attention, the law requires us to police the violation, otherwise we may lose the right to claim them.
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Q: Isn’t H.P. Lovecraft/Cthulhu Mythos in the public domain?
A: Not all aspects of H.P. Lovecraft’s work or the Cthulhu Mythos are in the public domain. Although H.P. Lovecraft was the originator of the Mythos, he generously collaborated with a wide circle of writers, and since his death others have continued to contribute to its ongoing creation. Included in this group are such names as August Derleth, Robert Bloch, Clark Ashton Smith, Brian Lumley, Ramsey Campbell, Sandy Petersen, and Chaosium itself, among others.
A: So you're not trying to claim you "own" the Mythos?
A: We make no claim that we "own" the Mythos, never have. Because HPL died over 70 years ago, his individual writings are now in the public domain, but the Mythos was/is a shared creation—even in HPL's lifetime ("the Lovecraft Circle"). Many of the writers HPL collaborated with lived on much later into the 20th century, e.g. Clarke Ashton Smith (d.1961), August Derleth (d.1971), Robert Bloch (d.1994), etc. Certain elements of the Mythos are theirs, or have been created by still-living authors including Brian Lumley, Ramsey Campbell and indeed Chaosium's Sandy Petersen. What these writers created in the Mythos won't enter the public domain until they have been dead for 70 years (or in Sandy's case, maybe never, because he is clearly an Immortal Being). We don't claim to own the Mythos in general (although certain elements of it are Chaosium IP), but we do own the Call of Cthulhu RPG, and and are obliged to protect it.