Essays by noted science-fiction writers and critics on the nine major themes of the genre, accompanied by 26 representative, exemplary stories -- Essays: The Remarkable Adventure (Philip José Farmer), Beyond Reality's Barriers (Robert Silverberg), Aliens (James E. Gunn), The Scientist (L. Sprague de Camp), The Machine and the Robot (Isaac Asimov), More Than Human?: Androids, Cyborgs, and Others (George Zebrowski), The City (Theodore Cogswell), Utopias and Dystopias (Martin H. Greenberg, Frederik Pohl) e Apocalypse (Jack Williamson).
Ficção científica