According to Wikipedia: "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 produced numerous popular detective books, ostensibly based on his own exploits and those of his agents. Some were published after his death, and they are considered to have been more motivated by a desire to promote his detective agency than a literary endeavour. Most historians believe that Allan Pinkerton hired ghostwriters, but the books nonetheless bear his name and no doubt reflect his own views."