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.
American comic book comic book schools globally, along with Japanese manga and the Franco-Belgian comic books. The typical size and page count of comics has varied over the decades, generally trending toward smaller formats and fewer pages. In recent decades, standard comics have been about × , and usually 32 pages long. While comics can be the work of a single creator, the labor of making them is frequently divided between a number of specialists. There may be a separate writer and artist, or there may be separate artists for the characters and backgrounds. Particularly in superhero comic books, the art may be