Superman (real name Clark Kent on Earth and Kal-El on Krypton), also known as "The Man of Steel" and "The Man of Tomorrow," is a Kryptonian-American superhero based out of Metropolis. He is widely considered to be the most influential character of the DC Universe, making up one-fourth of the "Trinity" (along with Batman and Wonder Woman) and according to modern continuity he is a founding member of the Justice League of America. As his alter-ego, the mild-mannered Kent, he is a journalist for the Daily Planet and is married to star colleague Lois Lane.
His first appearance in Metropolis, saving the Constitution space plane, sparked what is considered to be the "modern heroic age" of his Earth, and he has since been involved in nearly all of its most noteworthy events, including all three "Crises." He was briefly presumed dead after a catastrophic battle with Doomsday, and disappeared after losing his powers following Infinite Crisis. He also was a key player in the ousting of President Lex Luthor.
As one of the most powerful beings in the DCU, he possesses an array of powers including near-invulnerability, flight, super-speed, and heightened senses like super-hearing and X-ray vision. His most notable enemies are media mogul Luthor, the super-intelligent Brainiac, the kryptonite-wielding Metallo, and fellow Kryptonian survivor General Zod. Over the years he has gained sidekicks like Supergirl and the late Superboy.
The 1978 film Superman: The Movie, directed by Richard Donner, was an epic retelling of Superman's origin, with Christopher Reeve in the title role. Very much inspired by the "Silver Age" Superman, this portrayal also had its influence on the John Byrne reboot, as well as (and much more heavily) the current version as concocted by Geoff Johns, Kurt Busiek, and Donner himself. This character existed in the original series - Superman: The Movie, Superman II, Superman III, and Superman IV: The Quest for Peace - as well as the 2006 sequel Superman Returns, directed by Bryan Singer and portrayed by Brandon Routh.
It has been confirmed that the next Superman film will be a reboot of the series, not a continuation of the "Donner films."