The character of Hammer was created by Spillane, debuting in the 1947 book "I, the Jury", that was adapted into a feature in 1953 and 1982.
Prior to World War II, Spillane was a writer of comic books for Timely (now Marvel) Publications. After the war, he used what would be the plot of "I, the Jury" for a comic book character called 'Mike Danger' that eventually became 'Mike Hammer' in hard cover.
Hammer was a Marine veteran of the 'Battle of Guadalcanal'. As a private investigator he carries a .45 Colt in a shoulder holster under his left arm. His love for his secretary 'Velda' is only outweighed by his willingness to kill a killer.
While pulp detectives such as 'Sam Spade' and 'Philip Marlowe' are hard-boiled and cynical, Hammer is brutally violent, with a genuine rage against violent crime. In Spillane's "The Big Kill", Hammer describes himself to a bargirl as a 'misanthrope'.
While other heroes would bend and manipulate the law, Hammer often views it as an impediment to justice, the one virtue he holds in absolute esteem.
Hammer nevertheless has a strong respect for the police, realizing they have a difficult job, with their hands frequently tied by the law when trying to stop criminals. Because of this, Hammer is a cynical loner, contemptuous of the 'tedious process' of the legal system, choosing instead to enforce the law on his own terms.
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