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.
Batman
Batman was one of the few superhero characters to be continuously published as interest in the genre waned during the 1950s. In the story "The Mightiest Team in the World" in "Superman" #76 (June 1952), Batman teams up with Superman for the first time and the pair discover each other's secret identity. Following the success of this story, "World's Finest Comics" was revamped so it featured stories starring both heroes together, instead of the separate Batman and Superman features that had been running before. The team-up of the characters was "a financial success in an era when those were few and far between"; this series of stories ran until the book's cancellation in 1986.