Batman
The first Batman story, "The Case of the Chemical Syndicate", was published in "Detective Comics" #27 (May 1939). Finger said, "Batman was originally written in the style of the pulps", and this influence was evident with Batman showing little remorse over killing or maiming criminals. Batman proved a hit character, and he received his own solo title in 1940 while continuing to star in "Detective Comics". By that time, Detective Comics was the top-selling and most influential publisher in the industry; Batman and the company's other major hero, Superman, were the cornerstones of the company's success. The two characters were featured side-by-side as the stars of "World's Finest Comics", which was originally titled "World's Best Comics" when it debuted in fall 1940. Creators including Jerry Robinson and Dick Sprang also worked on the strips during this period.
Action Comics 1
"Action Comics" #1 (cover dated June 1938) is the first issue of the original run of the comic book/magazine series "Action Comics". It features the first appearance of several comic book heroes—most notably the Jerry Siegel and Joe Shuster creation, Superman—and sold for 10 cents (). It is widely considered to be both the beginning of the superhero genre and the most valuable comic book in the world. "Action Comics" would go on to run for 904 numbered issues (plus additional out-of-sequence special issues) before it restarted its numbering in the fall of 2011. It returned to its original numbering with issue #957, published on June 8, 2016 (cover-dated August).