Robert Anson Heinlein (/ˈhaɪnlaɪn/; July 7, 1907 – May 8, 1988) was an American science fiction writer. Often called the "dean of science fiction writers", he was an influential and controversial author of the genre in his time.

He was one of the first science fiction writers to break into mainstream magazines such as The Saturday Evening Post in the late 1940s. He was one of the best-selling science fiction novelists for many decades, and he, Isaac Asimov, and Arthur C. Clarke are often considered to be the "Big Three" of science fiction authors.