A deeply researched account of the life and legacy of the man who defined the profession of private eyeAllan Pinkerton, the world's most famous private detective, has been an enduring source of fascination since the nineteenth century. But the details of his impact, business empire, and private life have been incomplete.Drawing on overlooked primary sources, Rhodri Jeffreys-Jones provides an authoritative account of the man and the Pinkerton National Detective Agency (PNDA). It is the story of how PNDA's founder and its successive generations of heirs put it at the center of American history for decades. A small sampling of Pinkerton's activities includes providing intelligence in the Civil War, pursuing high-profile outlaws like Butch Cassidy and the Sundance Kid, and protecting scabs in the Homestead lockout, for which they became notorious. The book continues telling PNDA's history into the twentieth century and analyzes the legacies of Pinkertonism up to the present.General readers as well as scholars of American history will be fascinated by this rich new portrait of Pinkerton's accomplishments, controversies, and contradictions.