"Science fiction, American." . . "Fantasy fiction." . . "1900 - 1999" . . . . . . . . . "Universe" . "Universe"@en . . . . . . . . . . . . . "Science fiction"@en . . . . . "The chapters consist of essays by astronomers, speculations by science fiction authors, and illustrations by space artists and deep space photographers. Writers include Isaac Asimov, Gregory Benford, Ben Bova, Ray Bradbury, David Brin, William J. Kaufmann, Frederik Pohl, Allan Sandage, Robert Silverberg, Hyron Spinrad, Connie Willis, and others." . . . "Periodicals" . . . . . . . . "The Universe" . "The Universe"@en . . . . . . "Universe thirteen"@en . "Future, The, in literature." . . "Future, The, in literature Periodicals." . . "Time travel." . . "Fantasy fiction Periodicals." . . "Universe." . . "American literature." . . "Science fiction, American Periodicals." . . "American literature 20th century Periodicals." . . . . "Time travel Periodicals." . .