On a whim I just checked on H. P. Lovecraft’s year of death – it was 1937. This means that his works are now in the Public Domain here in Europe and, as Wikipedia states, likely in the United States and other countries, as well.
This is excellent news for everybody who loves the Cthulhu Mythos and would like to incorporate it in their own works, or expand upon it. I certainly have a few ideas myself. Of course care must be taken not to base your works off of something else that is derivative of Lovecraft’s work, such as the Call of Cthulhu role playing game, which obviously were created later and are therefore still protected.
Disclaimer: This is not legal advice, consult your lawyer before messing with anything legal 🙂