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.
Batmania
Kane's 6-page letter (reprinted by Roy Thomas in the pages of "Alter Ego", as published by TwoMorrows Publishing) was written on September 14, 1965, and after congratulating White on "Batmania" aims to rebut the various "myths" surrounding the creation of Batman. Opening his attempts to "explode the myths" about the creation of Batman, Kane writes:
The letter sparked a debate among comics fandom over the contributions made by Kane, Finger and Jerry Robinson (among others), a debate that continues to the present day. The letter itself, while much less charitable towards Finger than Kane would later be, appears carefully worded to rebut "the impression that "he" [Finger] and not myself [Kane] created the "Batman," as well as Robin[, etc.]" rather than to address Bails' issue of co-creatorship. Part of Kane's logic hinges on Finger's signature/by-line not appearing on the strip, even though such anonymity and relinquishing of credit was commonplace in the comics industry of the 1930s and 1940s. Kane further threatens legal action against Jerry Bails, asserting that, while Finger "was influential . . . in shaping up the strip", the idea was conceived solely by him prior to bringing Finger in to script the work, and therefore was created solely by him. "Batmania" – and other forums – have since debated whether the "influential" assistance of Finger was deserving of more credit than Kane was – at the time – willing to apportion him.