Allan Pinkerton (1819–1884) was a Scottish-American detective, spy, and founder of the Pinkerton National Detective Agency, one of the first and most influential private detective organizations in the United States. Born in Glasgow, Scotland, he emigrated to America in 1842 and worked as a barrel maker before gaining recognition for uncovering a counterfeiting ring. In 1850, he established the Pinkerton Agency, which became renowned for solving high-profile crimes, providing security for railroads, and conducting espionage during the Civil War, including foiling an assassination plot against President Abraham Lincoln.

Pinkerton was also a prolific writer, publishing numerous accounts of his cases and detective methods, such as The Expressman and the Detective (1874), The Spy of the Rebellion (1883), and other works that blended fact and fiction to dramatize the exploits of his agency. His writings offered insights into early detective work and helped shape the public's fascination with private investigators. Pinkerton's legacy endures in the fields of law enforcement and security, as well as in the literary history of detective and crime fiction. He died in 1884 but remains an iconic figure in the history of American criminal investigation.