Nick and Nora Charles the bantering, romantically involved detective duo has become a well-used trope in literature, stage, screen, and television ever since. The characters first appear in Dashiell Hammett's best-selling last novel "The Thin Man" (1934). Nick is an alcoholic former private detective who retired when he married Nora, a wealthy Nob Hill heiress. Hammett reportedly modeled Nora on his longtime partner Lillian Hellman, and the characters' boozy, flippant dialogue on their relationship. (The novel also mentions that Nick was once a Pinkerton detective, as was Hammett.) The novel is considered one of the seminal texts of the hard-boiled subgenre of mystery novels,
Allan Pinkerton affiliated with the notorious Banditti of the Prairie. After observing their movements for some time he informed the local sheriff, who arrested them. This later led to Pinkerton being appointed, in 1849, as the first police detective in Chicago, Cook County, Illinois. In 1850, he partnered with Chicago attorney Edward Rucker in forming the North-Western Police Agency, which later became Pinkerton & Co, and finally Pinkerton National Detective Agency, still in existence today as Pinkerton Consulting and Investigations, a subsidiary of Securitas AB. Pinkerton's business insignia was a wide open eye with the caption "We never sleep." As the US