For centuries, New York had been a haven of crime, but in the early 1870s, Irish cop Thomas Byrnes developed new ways to catch criminals: Mug shots, daily lineups that helped witnesses point out culprits, and the third-degree interrogation method. In response, lawbreakers became more ruthless and better organized, with corrupt cops and clever criminals at times blurred together. John Oller's history of Gilded Age law enforcement has a colorful cast that includes Theodore Roosevelt as well as a matronly German-immigrant thief, a Tammany Hall crook, and a Sicilian detective who battled the Black Hand.