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,
Arnstein v. Porter facts," clarifying that expert testimony is allowed on cases dealing with copyright of songs. The court also stated that in the absence of direct evidence of copying, "the similarities [between the works] must be so striking as to preclude the possibility that plaintiff and defendant independently arrived at the same result." Ultimately, the court found that whether two songs were substantially similar enough to constitute copyright infringement was a matter of fact for a jury to decide, so they remanded the case for a jury trial. Arnstein v. Porter Arnstein v. Porter, 154 F.2d 464 (2d Cir. 1946) is a