Van Vogt's first SF publication was inspired by The Voyage of the Beagle by Charles Darwin. "The Black Destroyer" was published in July 1939 by John W. Campbell in Astounding Science Fiction, the centennial year of Darwin's journal. It featured a fierce, carnivorous alien, the coeurl, stalking the crew of an exploration spaceship, and served as the inspiration for multiple science fiction movies, including Alien (1979).
Also in 1939, still living in Winnipeg, van Vogt married Edna Mayne Hull, a fellow Manitoban. Hull, who had previously worked as a private secretary, would act as van Vogt's typist, and be credited with writing several SF stories of her own throughout the early 1940s.
The outbreak of World War II in September 1939 caused a change in van Vogt's circumstances. Ineligible for military service due to his poor eyesight, he accepted a clerking job with the Canadian Department of National Defence. This necessitated a move back to Ottawa, where he and his wife would stay for the next year and a half.