American comic book Kane and Bill Finger created Batman, who debuted in "Detective Comics" #27 (1939). The period from the late 1930s through roughly the end of the 1940s is referred to by comic book experts as the Golden Age of comic books. It featured extremely large print-runs, with "Action Comics" and "Captain Marvel" selling over half a million copies a month each; comics provided very popular cheap entertainment during World War II especially among soldiers, but with erratic quality in stories, art, and printing. In the early 1940s over 90 percent of girls and boys from seven to seventeen read comic books.
Superhero fiction detective the Clock, who debuted in Centaur Publications' "Funny Pages" #6 (Nov. 1936). Historians point to the first appearance of Superman, created by Jerome "Jerry" Siegel and designed by Joseph "Joe" Shuster, in "Action Comics" #1 (June 1938) as the debut of the comic-book archetype of the superhero. Outside the American comics industry, superpowered, costumed heroes such as Ōgon Bat (1931) and the (1930s), were visualized in painted panels used by kamishibai oral storytellers in Japan. In 1938, writer Jerry Siegel and artist Joe Shuster, who had previously worked in pulp science fiction magazines, introduced Superman. (Siegel, as the writer,