Originally published in 1929, DETECTIVE DUFF UNRAVELS IT gathers eight short stories by Harvey O'Higgins featuring the titular detective doing what no literary detective had done previously—namely, using psychology to solve cases. This novel approach helped the book take its place as a major work of crime fiction in the highly regarded QUEEN'S QUORUM list by mystery writer Ellery Queen. This volume includes two previously uncollected Duff tales, bringing all the Duff stories together for the first time.

Once a lawyer before the war, private detective John Duff might still be a lawyer to anyone looking—albeit an unsuccessful one, in a shabby office in a decrepit building just off Manhattan's Union Square. The deception suits his method, which is keeping a low profile. Duff employs a network of operatives who pose as businessmen, private care nurses. or housekeepers, whom he moves about like chess pieces to gain psychological insights into his clients and suspects. From murder to extortion to kidnapping and more, Detective Duff unravels it all, using his shrewd understanding of human behavior and his expert team of operatives to pick apart even the knottiest of cases.