Allan Pinkerton (25 August 1819 – 1 July 1884) was a Scottish American detective and spy, best known for creating the Pinkerton National Detective Agency, the first detective agency of the United States.
Pinkerton married Joan Carfrae (a singer) in Glasgow on 13 March 1842 secretly before moving to America. Disillusioned by the failure to win suffrage, Pinkerton emigrated to the United States in 1842, at the age of 23.
In 1849 Pinkerton was appointed as the first detective in Chicago. In the 1850s, he partnered with Chicago attorney Edward Rucker in forming the North-Western Police Agency, later known as the Pinkerton National Detective Agency and still in existence as Pinkerton Consulting and Investigations, a subsidiary of Securitas AB. Pinkerton's business insignia was a wide open eye with the caption "We never sleep." As the United States expanded in territory, rail transportation increased. Pinkerton's agency solved a series of train robberies during the 1850s, first bringing Pinkerton into contact with George McClellan and Abraham Lincoln.
To read more about Allan Pinkerton, visit his page on Wikipedia.