Powered armor (also called CAS or Combat Armored Suits) has appeared in a wide variety of fiction, beginning with E. E. Smith's Lensman series in 1937. Since then, it has featured in science fiction movies and literature, comic books, video games, and tabletop role-playing games. One of the most famous early versions was Robert A. Heinlein's 1959 novel Starship Troopers, which can be seen as spawning the entire sub-genre concept of military "powered armor."