The first issue of Action Comics featuring Superman debuted in 1938.
Action Comics #1 went on sale on April 18, 1938, with a cover date of June 1938. Published by National Allied Publications, a predecessor of DC Comics, the issue introduced Superman to a mass audience and is widely regarded as the beginning of the superhero-comic-book era. The cover showed Superman lifting a car above his head.
The issue was an anthology rather than a Superman-only comic, featuring several different stories and characters. Jerry Siegel wrote the Superman story and Joe Shuster drew it. Their creation presented a powerful visitor from the doomed planet Krypton who was raised on Earth as Clark Kent and used his abilities to protect people.
A frequent source of confusion is the difference between publication date and cover date. April 18, 1938 is the on-sale date, while June 1938 is the printed cover date; both refer to Action Comics #1. The issue originally sold for 10 cents, and its success helped establish Superman as the flagship character of what became DC Comics.