Comics are collected for several possible reasons, including appreciation, nostalgia, financial profit, and completion of the collection. The comic book came to light in the Pop culture arena in the 1930s due to 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.