Storyline
The Mad Hatter wants to add Batman's cowl to his collection of hats, and he goes through a series of elaborate schemes to secure it, which he does.
Story Notes
1966 Batman TV Series, episodes 69 ("The Contaminated Cowl") and 70 ("The Mad Hatter Runs Fowl"), were based on this story.
1st appearance of the second Mad Hatter. The first Mad Hatter appeared in Batman (DC, 1940 series) #49 (October-November 1948). This Mad Hatter is later revealed as an impostor.