Prolific writer (1909–1971), known for his contributions to the Cthulhu Mythos genre of horror, a shared fictional universe based on the writings of H. P. Lovecraft. Hardcover book, Wind over Wisconsin, 5.5 x 8.25, signed and inscribed on the half-title page, “For Miss Janie Quimby—for whose generous and kind assistance I am grateful—with every good wish, cordially, August Derleth, April 22, 1938”; and a TLS, signed in pencil, one page, 7.25 x 7.75, personal letterhead, May 12, 1944, tipped in to the first free end page of a hardcover edition of Shadow of Night. Letter reads, in part: “It gives me pleasure to know that you enjoyed Shadow of Night; as a book, it was I think more carefully written than some earlier novels, and it was also somewhat more enthusiastically received by the critical fraternity. But your trip down the river sounds more interesting than my book…It is the kind of trip Thoreau used to make from time to time, to ‘refresh’ and ‘renew’ himself—a good thought surely!” In fine condition, with mild toning to pages and letter, sunning to one of the spines, and scattered light wear to covers. RR Auction COA.