I always wondered about the Secret Service and how it came about. When I saw it was Chicago-based Pinkerton, I went deeper. I knew he gave up on catching Jesse James, had other foibles before and during the war; A very controversial figure--IMO, sometimes hypocritical in his actions. His loyalty to McClellan was surprising to me (but that is based on my poor opinion of McClellan, just an opinion). His numbers?--pretty reliable. His ideas?--bold and worth study. Good book I have, "Allen Pinkerton: The First Private Eye, by J. Mackay" (the only one so far I own), is a good source about him.