Detective Comics #27 is an American comic book of the Detective Comics anthology series known for debuting the superhero Batman in a featured story called "The Case of the Chemical Syndicate" during the Golden Age of Comic Books. It is considered one of the most important and valuable first appearance debuts from DC Comics alongside Action Comics #1, released the previous year. In addition to the debut of Batman, Detective Comics #27 included several other stories featuring established and original characters. These features represented the range of genres covered by the anthology series at the time, including crime, espionage, western, and mystery fiction.