Superman the offer. Siegel and Shuster submitted their work in late February and were paid $130 (AFI $) for those 13 pages. In early March they signed a contract (at Liebowitz's request) in which they released the copyright for Superman to Detective Comics, Inc. This was normal practice in the business, and Siegel and Shuster had given away the copyrights to their previous works as well. Superman was finally published on April 18, 1938, in the first issue of "Action Comics". The magazine sold very well, and feedback from readers showed it was because of Superman. Siegel and Shuster read pulp
Superman Universe, which is a shared universe of superhero characters owned by DC Comics, and consequently he frequently appears in stories alongside the likes of Batman, Wonder Woman, and others. Superman has sold more comic books over his lifetime than any other American superhero character. Exact sales figures for the early decades of Superman comic books are hard to find because, like most publishers at the time, DC Comics concealed this data to deny competitors, but sales of "Action Comics" and "Superman" probably peaked in the mid-1940s and thereafter steadily declined as part of a general trend in comic book sales.