Batman No. 1 is a landmark comic book issue published by DC Comics in 1940, featuring the first appearances of the Joker and Catwoman. Created by Bill Finger, Bob Kane, and Jerry Robinson, the Joker emerges as a homicidal maniac with a flair for theatrics, while Catwoman debuts as a jewel thief, adding intrigue and romantic tension to Batman's world. The issue also introduces iconic elements like the Batplane and the Batcave, solidifying Batman's status as a legendary crime-fighting superhero.