first private detective agency. Recounting true events, `The Expressman and the Detective‘ (1874) tells a fascinating and suspenseful story of an investigation in which all that can prove a person‘s guilt is a confession. Allan Pinkerton, the founder of the agency, assigned agents to shadow the suspect, others to gain his trust and he was among the first to hire a female detective. The London Times famously called him "a man at once deeply admirable and quite obnoxious."

Allan J. Pinkerton(1819-1884) was a Scottish-American detective and founder of the Pinkerton National Detective Agency. He recounted his first big investigation in `The Expressman and the Detective.‘ A dedicated abolitionist, he offered his Illinois home as a stop on the Underground railway for escaping slaves.