Scottish American detective and spy who served in the Union Army during the civil war and opened the Pinkerton National Detective Agency.
He moved from Scotland to the United States in 1842 and began working with the abolitionist movement in 1844, including providing his house to the Underground Railroad.
At the time of his death, he was working on a system to centralize criminal records. The system was later developed and maintained by the FBI.
He married Joan Pinkerton in 1842, and they had two children named William and Robert.
He is said to have foiled an assassination attempt on President Abraham Lincoln in 1861.