Dennis Lehane has extended the gritty realism of James Ellroy and James Crumley to the traditional private detective form. His first novel, A Drink Before the War (1994), won the Shamus Award for best first novel. In the next four novels in the Patrick Kenzie and Angela Gennaro series, Lehane continued to explore the darkest recesses of human behavior, with a collection of violent and grotesque characters few writers would even have attempted. Though he admits that elements of the thriller and more generic crime writing are present in his work and he is clearly aware that he is working within the conventions of the private investigator novel, when asked to classify his own writing, Lehane calls it noir.
Despite the dark tone, there is always an undercurrent of comedy in his novels, from the flippancy of the Patrick-Angie relationship to the comic, clownishly dressed would-be enforcers of Sacred (1997) to Cheese Olamon, the 430-pound Swede who thinks he is an African American. Some critics have complained that Lehane inappropriately mixes tones, switching from the comic to the unbearably gruesome in his works, but his comedy is more organic to his plots than are the wisecracks included by Raymond Chandler or Robert B. Parker. Sacred won a Nero Award and was nominated for a Shamus.
Even when Lehane felt he had exhausted the detective form after five Kenzie-Gennaro novels, he continued to write about crime, mystery, and the horrifying. Mystic River (2001), his best-known work and a critically acclaimed best seller, is imprinted with the style and themes of his series novels—murder, the presence of evil, and the impact of evil on whole generations—but without a detective as a major presence. Shutter Island (2003), an unsettling psychological thriller about a United States marshal trapped in an asylum for the criminally insane on an island during a hurricane, has a surprise ending that goes well beyond the mere unmasking of a killer and questions the very nature of reality and perception.
In 2002, Mystic River became a finalist for the L. L. Winship/PEN New England Award (for best book about New England) and won both the Anthony Award and the Barry Award for best novel of the year.