October the First Is Too Late (1966) is similar to that of Leinster's story, except that the segments of Earth which are brought together and interact with each other are from different historical periods, rather than from different parallel histories. In his comments on the story in Before the Golden Age, Isaac Asimov writes that "Sidewise in Time" had a long-term effect on his thinking. "It always made me conscious of the 'ifs' in history, and this showed up not only in my science fiction, as in 'The Red Queen's Race', but in my serious books on history as well. I also used the alternate-history theme, in enormous complexity, in my novel The End of Eternity." Themes touched upon by Leinster would be taken up at greater length by others: Confederate victory in the American Civil War, a Roman Empire which never fell, enduring Viking colonization of America, Russia keeping its 19th-century colonies in Pacific America, Chinese colonists finding their way to America. The idea of a scholar using a cataclysmic event to make himself the ruler of primitive people was taken up by S. M. Stirling in the Nantucket and Emberverse series, where the main villains do this repeatedly. Publication history Astounding Stories, June 1934 Sidewise in Time, edited by Murray Leinster, Shasta, 1950 Worlds of Maybe, edited by Robert Silverberg, Dell, 1970 Before the Golden Age, edited by Isaac Asimov, Doubleday, 1974 The Best of Murray Leinster, edited by J.J. Pierce, Del Rey, 1978 The Time Travellers—A Science Fiction Quartet, edited by Robert Silverberg & Martin H. Greenberg, Donald I. Fine, 1985 Great Tales of Classic Science Fiction, edited by Isaac Asimov, Martin H. Greenberg & Charles Waugh, Galahad, 1988 First Contacts, edited by Joe Rico, NESFA Press, 1998 References External links 1934 short stories Alternate history novels set in ancient Rome Alternate history short stories American Civil War alternate histories American short stories Works by Murray Leinster Works originally published in Analog Science Fiction and Fact