Michael "Mike" Hammer is a fictional detective created by the American author Mickey Spillane in the 1947 book I, the Jury (made into a movie in 1953 and 1982).
Several movies and radio and television series have been based on the books in the Hammer series. The actor most closely identified with the character in recent years has been Stacy Keach, who portrayed Hammer in a CBS television series, Mickey Spillane's Mike Hammer, which ran from 1984–1987 and had a syndicated revival in 1997–1998. (An earlier syndicated version, originally aired in 1957–1958, starred Darren McGavin as Hammer.) Spillane himself played Hammer in a 1963 motion picture adaptation of The Girl Hunters. Spillane himself favoured ex-Marine and former Newburgh, New York police officer Jack Stang, on whom he based the character, to play him. Stang appeared with Spillane in the 1954 film Ring of Fear and in the film adaptation of I, the Jury.
While pulp detectives such as Sam Spade and Philip Marlowe are hard-boiled and cynical, Hammer is in many ways the archetypal "hard man": brutally violent, misogynistic, and fueled by a genuine rage that never afflicts Raymond Chandler's or Dashiell Hammett's heroes. In The Big Kill Hammer describes himself to a bargirl as a misanthrope.