I just finished this book - it's about the life of Pryce Lewis, a detective and spy for the Union. It's a heck of a story and I really enjoyed reading it.
Here is some more information on this book should you be intrigued. If you go down the linked page to almost the end, there is a tab for Published Reviews by the pros and beneath that a tab for Reviews from GoodReads by the rest of us.
Emigrating to the United States in 1856, Pryce Lewis was soon employed as an operative by Allan Pinkerton in his newly established detective agency. Early in the Civil War Pinkerton offered the agency to President Lincoln as a secret service, spying on Southern forces and insurrectionists...