The detective novel has existed, in one form or another, for over 150 years, enough time for it to develop well codified genre characteristics. Although these are the subject of constant modification by authors, indeed a source of creativity and object of reader interest, there is enough consistency among them to permit classification and discussion. Below are links to pages discussing the main features.
William Marling's “L.A. - City of Sleuths” in the Cambridge Companion to the Literature of Los Angeles (2010).
The prototypical LA detective was invented in San Francisco by Dashiell Hammett. Whether his name was The Continental Op or Sam Spade, he was hard-boiled, with a blue-collar attitude, edgy repartee, and a close connection to his setting. Hammett used him to portray the city, its political corruption, its fog and docks and hills, its cab drivers and efficiency apartments. By 1925 the Op was already a working stiff who suffered for his drinking bouts. With a few changes, he became Sam Spade, the iconic hero of The Maltese Falcon (1930). (continue)
The Bouchercon World Mystery Convention has been held annually in various cities since 1970 but has never been hosted in Ohio. The Bouchercon itself, and the Anthony Awards, which are announced at the conference, are named in honor of author, editor and mystery devotee, Anthony Boucher. The theme of the 2012 conference will be "Crime Fiction Rocks," with the opening ceremonies to be held at the Rock & Roll Hall of Fame and Museum. More info.