A collection of twenty classic short stories by Isaac Asimov, author of the Foundation series, featuring the definitive and only in-print version of "Nightfall" From one of history's most influential writers of science fiction comes this collection of twenty short works of fiction, arranged in order of publication from 1941 to 1967. Compiled by Asimov himself, who prefaced each story with an introduction, it begins with "Nightfall," the tale of a world with eternal sun that is suddenly plunged into total darkness and utter madness. "Nightfall," published when the author was only twenty-one, was arguably his breakout work, making such an impression that, almost thirty years later, the Science Fiction Writers of America voted it the best science-fiction short story ever written The other stories in the collection span far and wide: A dedicated scientist who whips up his own love potion. Machines that learn to think for themselves--and direct their thoughts to overturning the establishment. The discovery that Earthlings are being destroyed by a mysterious kind of psychological virus. A day when walking outdoors becomes a sign of psychosis. And many more.