By the time his UFO books appeared, Keyhoe was already a well-established author, with numerous appearances in the pulp magazines of the 1920s and 1930s. Four of his short stories were printed in "Weird Tales", one of the most prestigious of the pulps: "The Grim Passenger" (1925), "The Mystery Under the Sea" (1926), "Through the Vortex" (1926) and "The Master of Doom" (1927). He also produced the lead novel for all three issues of a short-lived magazine called "Dr. Yen Sin": "The Mystery of the Dragon's Shadow" (May/June 1936), "The Mystery of the Golden Skull" (July/August 1936) and "The Mystery of the Singing Mummies" (September/October 1936). The Doctor was opposed by a hero who could not sleep.