What DC Comic book did the Joker originally appear in 1940?
The Joker (comic book): The Joker is a comic book series published by DC Comics starring the super-villain the Joker. Joker (character): The Joker is a fictional supervillain created by Bill Finger, Bob Kane, and Jerry Robinson who first appeared in the debut issue of the comic book "Batman" (April 25, 1940), published by DC Comics.
Batman