Major Key
Action Comics #1
First appearance of Superman and the beginning of the superhero genre.
View key issue guideMarvel & DC Key Comic Issues
Explore 279 collector guides covering major and minor Marvel & DC comic milestones.
Major Key Comic Issues
Browse major milestones, debuts and defining comic-book keys.
279 major key issues
Major Key
Detective Comics #27
First appearance of Batman, introducing Bruce Wayne’s masked crime-fighting identity in a landmark Golden Age story.
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Major Key
Captain America Comics #1
First appearance of Bucky Barnes alongside Captain America.
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Major Key
Sensation Comics #1
First Wonder Woman cover feature and beginning of her regular solo adventures.
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Major Key
Wonder Woman #1 (1942)
Launch of Wonder Woman's first solo title and expanded origin.
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Major Key
Superman #30
First appearance of Mister Mxyzptlk in the Superman title.
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Major Key
Venus #6
Minor historical key — early Marvel-era appearance of a Loki character.
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Major Key
Detective Comics #168
The Red Hood story provides a foundational origin for the Joker.
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Major Key
Batman #121
First appearance of Mister Freeze, originally introduced as Mr. Zero.
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Major Key
Detective Comics #230
First appearance of the original Batwoman, Kathy Kane.
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