Robert A. Heinlein. Robert Anson Heinlein (/ˈhaɪnlaɪn/ HYN-lyn;[1][2][3] July 7, 1907 – May 8, 1988) was an American science fiction writer. Often called the "dean of science fiction writers",[4] he was one of the most influential and controversial authors of the genre in his time. He set a standard for scientific and engineering plausibility, and helped to raise the genre's standards of literary quality. He was one of the first science fiction writers to break into mainstream magazines such as The Saturday Evening Post in the late 1940s. Future History. Lazarus Long. His exact (natural) life span is never determined.
In his introduction at the beginning of Methuselah's Children, he admits he is 213 years old. Approximately 75 years pass during the course of the novel; but because large amounts of this time are spent traveling interstellar distances at speeds approaching the speed of light, the 75-year measurement is an expression of the time elapsed in his absence rather than time seen from his perspective. At one point, he estimates his natural life span to be around 250 years; but this figure is not expressed with certainty. Heinlein acknowledged that such a long life span should not be expected as a result of a mere three generations of selective breeding, but offers no alternative explanation except by having a character declare, "A mutation, of course—which simply says that we don't know".[2]
World as Myth.