Batman is an ongoing superhero comic book series published by DC Comics, featuring the character of the same name as its protagonist. The character, created by Bill Finger and Bob Kane, first appeared in Detective Comics #27. Batman proved to be so popular that a self-titled ongoing comic book series began publication with a cover date of spring 1940. It was first advertised in early April 1940, one month after the first appearance of his new sidekick, Robin the Boy Wonder.