The Case of Charles Dexter Ward
The story contains the first mention of Abdul Alhazred, a fictional authority on the occult who would later be mentioned in most of Lovecraft's major Cthulhu Mythos stories, including "The Hound" (1922), "The Festival" (1923), "The Call of Cthulhu" (1926), "The Case of Charles Dexter Ward" (1927), "The Dunwich Horror" (1928), "The Whisperer in Darkness" (1930) "At the Mountains of Madness" (1931), "The Dreams in the Witch House" (1932), "The Thing on the Doorstep" (1933), and "The Shadow out of Time" (1934).