Friday is a 1982 science fiction novel by Robert A. Heinlein. It is the story of a female "artificial person", the eponymous Friday, genetically engineered to be stronger, faster, smarter, and generally better than normal humans. Artificial humans are widely resented, and much of the story deals with Friday's struggle both against prejudice and to conceal her enhanced attributes from other humans. The story is set in a Balkanized 21st century, in which the nations of the North American continent have been split up into a number of smaller states.

Robert Anson Heinlein was an American science fiction author, aeronautical engineer, and naval officer. Sometimes called the "dean of science fiction writers", he was among the first to emphasize scientific accuracy in his fiction, and was thus a pioneer of the subgenre of hard science fiction. His published works, both fiction and non-fiction, express admiration for competence and emphasize the value of critical thinking. His plots often posed provocative situations which challenged conventional social mores. His work continues to have an influence on the science-fiction genre, and on modern culture more generally.