DASHIELL HAMMETT

According to Wikipedia: "Samuel Dashiell Hammett was an American author of hard-boiled detective novels and short stories. He was also a screenwriter and political activist. Among the enduring characters he created are Sam Spade (The Maltese Falcon), Nick and Nora Charles (The Thin Man), the Continental Op (Red Harvest and The Dain Curse) and the comic strip character Secret Agent X-9.

Hammett "is now widely regarded as one of the finest mystery writers of all time". In his obituary in The New York Times, he was described as "the dean of the ... 'hard-boiled' school of detective fiction.""

Check out Wikipedia's entry for a lot more info on this highly influential author.