New on Archive.org is W. Paul Ganley’s ‘zine Toadstool Wine (1975). The lead article was the non-fiction “The Literature of Cosmic Dread” by Fritz Leiber. Page 46 of the ‘zine also offers an October 1935 letter from Lovecraft on the craft of story-writing.

“He [Wright] says my stories are too long — and then proceeds to accept some interminable series from one of his regular hacks”.