Valley of Fear

The final Sherlock Holmes novel opens on a cipher, a murder at a moated Sussex manor with the victim's face destroyed by a shotgun, and the shadow of Professor Moriarty - then breaks, halfway through, to a Pennsylvania coal valley where a secret society rules the mines by terror. Conan Doyle drew that second half from the real Molly Maguires and the Pinkerton agent who broke them, and the two stor...