 Anderson published 21 novels, novellas and short stories set in this future between 1949 and 1957, with a 22nd published in 1968.Anderson did not write the stories in chronological order; instead, as Robert A. Heinlein did with his own Future History stories, he wrote whichever story in the series he wanted to, and trusted his readers to make the connections between them.Anderson included a series timeline in the Winter 1955 issue of" Startling Stories "to accompany the novella "The Snows of Ganymede".