In which Detective Series number did the fictional character Batman first appear in American comic books published by DC Comics in 1939?

Batman is a fictional character and superhero first appearing in American comic books published by DC Comics in March 1939. The character was created by artist Robert Kane and writer William Finger and first appeared in Detective Comics # 27. Originally named "Bat Man", the character is also referred to by such epithets as The Caped Crusader, The Dark Knight, and the World's Greatest Detective.

Batman is the alter ego of Bruce Wayne with team affiliations and partnerships including Robin, James Gordon, Wonder Woman, Catwoman and Batgirl to name a few.

In comics and then a television series, followed by a series of modern day movies, Batman has unique abilities including a genius-level intellect, a peak human physical condition, skilled martial arts and hand-to-hand combat; he is an expert detective and a superhero who uses high-tech equipment, weapons and a vehicle called a Batmobile.

Rober Kane (1915-1998) was an American comic book writer and artist. He was inducted into the comic book industry's Jack Kirby Hall of Fame in 1994 and into the Will Eisner Comic Book Hall of Fame in 1996.

William Finger (1914-1974) was also an American comic strip and comic book writer. Although Finger did not receive contemporaneous credit for his hand in the development of Batman, Kane acknowledged Finger's contributions years after Finger's death. He also was inducted into the same industry's recognized organizations, but posthumously.