The article doesn't explain why Lovecraft's works are in the public domain. Lovecraft's intention was that R.H. Barlow serve as executor of his literary estate.

The article doesn't explain why Lovecraft's works are in the public domain. Lovecraft's intention was that R.H. Barlow serve as executor of his literary estate. My recollection is that this was never properly carried out, so control over the estate devolved to his aunt, Annie Gamwell. Gamwell turned Lovecraft's papers over to Barlow who deposited most of them in the John Hay Library at Brown University. Throughout all of this, the copyright remained vested in Gamwell. In the 1940s, Derleth approached Gamwell's survivors and requesting permission to reprint his work and later fraudulently asserted copyright over the entire literary estate. Derleth also bought out the reprint rights for volumes of Weird Tales that contained Lovecraft's work, but Lovecraft had retained copyright for all stories in Weird Tales published after 1926. His output between 1924 and 1926 amounts to six stories as far as I can tell. Derleth may have legitimately obtained the copyright on these stories, but I can't say with any certainty. S.T. Joshi probably knows for sure. As for everything published after 1926, Gamwell's survivors never renewed the copyright on Lovecraft's work, so the body entered the public domain. Edit: I'll add that I'm disappointed that Lovecraft's letters aren't freely available. Arkham House hasn't printed his collected letters in nearly 40 years. If Brown were willing to make digital copies of his correspondence freely available, I'd be willing to contribute toward their digitization.