J. J.: Thanks for that. I defer to the heftier biography, which I never read. (Derleth’s was a slight thing, and my recollection of it vague. It seems to have sunk without trace: I can’t find it on Abebooks.com.)
From what you say, Lovecraft would fit comfortably into Jonah’s book somewhere, though there is no index entry for him. I still think he would have been a lousy socialist, though. Socialists are supposed to care about the toiling masses, which is not at all the impression one gets from Lovecraft’s fiction. Perhaps what he actually cared about was his own chronic — but entirely self-inflicted — poverty.