Sir Arthur Ignatius Conan Doyle (22 May 1859 – 7 July 1930) was a Scottish writer and physician, most noted for his fictional stories about the detective Sherlock Holmes, which are generally considered milestones in the field of crime fiction. "The Valley of Fear" is the fourth and final Sherlock Holmes novel by Sir Arthur Conan Doyle. It is loosely based on the real-life exploits[citation needed] of the Molly Maguires and Pinkerton agent James McParland. Holmes decodes a cipher warning from Moriarty's organization for "Douglas" in "Birlstone", but a corpse is there already. When Mr. Douglas blows the head off his American assassin, he dresses the body as himself, and hides, to throw off the chase for good. Holmes guesses the missing dumb-bell weighted down the killer's clothes in the moat... (Excerpt from Wikipedia)