Action Comics #1 was the first superhero comic book. Published in June 1938, it introduced Superman. Copies of the original sell for very high prices due to the history and rarity of the comic book. But age and rarity are not the only factors considered in the appraisal of comic books. Condition is also very important. You can learn more about your own comic books and what they’re worth by subscribing to a comic art publication or joining a comic art collector club.