Captain Marvel (DC Comics) Comics" #21 (1941) introduced the Lieutenant Marvels: three other boys named "Billy Batson" who could also become adult superheroes. Captain Marvel, Jr., the alter-ego of disabled newsboy Freddy Freeman, debuted in "Whiz Comics" #25 (1941). Mary Marvel, alter-ego of Billy's twin sister Mary Batson, first appeared in "Captain Marvel Adventures" #18 (1942). In contrast to Captain Marvel and the Lieutenants, both Mary Marvel and Captain Marvel, Jr. remained kids in superhero form, and were given their own eponymous books in addition to appearing as the lead features in "Master Comics" and "Wow Comics", respectively. Captain Marvel, Captain Marvel Jr., and
Comic book collecting the popularity of superhero characters Superman, Batman, and Captain Marvel. Since the 1960s, two publishers have dominated the American comic book industry: Marvel Comics, publisher of such comics as "Spider-Man", "X-Men", and "Fantastic Four", and DC Comics, which publishes titles such as "Superman", "Batman", and "Wonder Woman". Other large non-manga publishers include Image Comics, IDW, and Dark Horse Comics. As comic books regained their popularity in the 1960s during the boom of the Silver Age, fans organized comic book conventions, where they could meet to discuss their favorite comics with each other and eventually with the creators themselves. , numerous