"The unchanging nature of those Batman and Robin stories did not hurt their appeal to the young readers who were the main market for super-hero comics. In fact, the team became one of the most popular and enduring in the genre, appearing together in every issue of Detective Comics, and then Batman, and then with Superman on World's Finest. Indeed, the Boy Wonder was popular enough to appear on more ccomic-book covers in the 1940s than Batman himself."