A superhero (also known as a "super hero" or "super-hero") is a fictional character "of unprecedented physical prowess dedicated to acts of derring-do in the public interest." Since the debut of Superman in 1938 by Jerry Siegel and Joe Shuster, stories of superheroes — ranging from brief episodic adventures to continuing years-long sagas — have dominated American comic books and crossed over into other media. A female superhero is sometimes called a "superheroine." For a list of comic book supervillain debuts, see List of comic book supervillain debuts.