Hard science fiction is a category of science fiction characterized by concern for scientific accuracy and logic. The term was first used in print in 1957 by P. Schuyler Miller in a review of John W.
Arthur C. Clarke, one of the most influential writers of hard science fiction
Poul Anderson, author of Tau Zero, Kyrie and others
Frank R. Paul's cover for the last issue (December 1953) of Science-Fiction Plus
Larry Niven, author of Ringworld, "Inconstant Moon", "The Hole Man" and others
Soft science fiction, or soft SF, soft sci-fi, is a category of science fiction with two different definitions, in contrast to hard science fiction. It explores the "soft" sciences, as opposed to the
Hard science fiction
…by P. Schuyler Miller in a review of John W. Campbell's Islands of Space in the November issue of Astounding Science Fiction. The complementary term soft science fiction, formed by analogy to the popular distinction between the "hard" (natural) and "soft" (social) sciences, first appeared in the late 1970s. Though there…
Ursula K. Le Guin, one of the most significant writers of soft science fiction
Peter Nicholls, the first person attested to have used the term soft science fiction
H. G. Wells, an early example of a soft science fiction writer
Audrey Niffenegger, author of the soft science fiction work The Time Traveler's Wife