If you are like me, you may think of Pinkerton as a by-word for anti-union thugs. And you've probably seen Pinkerton armored cars driving about your town, armed and armored, and ready for war against Bonnie and Clyde to this very day. But this is a book about the other Pinkerton, the original one, the abolitionist Allan Pinkerton.
Before the Civil War Allan Pinkerton escorted John Brown and his party of escaping slaves to Canada. He invented the modern science/profession of detection. His Pinkerton Agency played a central role in thwarting the Baltimore assassination plot against Lincoln, prior to his inauguration. And, in the first years of the Civil War he invented the idea of the Secret Service, and ran spies and espionage operations against the South. His tale is a remarkable one, and well worth a few evenings. In the nature of a story about spies, this book conveys a great deal about the political and social world of the American polity in the early 1860s.
I don't know how his sons, who inherited the business, came to be union busters, but that is another story about different men and different times. The story of the original Pinkerton, Allan Pinkerton, is all about rising from rags and manual labor to become an emperor of intrigue, in the name of abolition and the cause of President Lincoln. Fun stuff, if you are of a certain mind.