The Valley of Fear
By Arthur Conan Doyle
Cover: Sherlock Holmes and Professor Moriarty at the Reichenbach Falls (1893), illustration by Sidney Paget (1860-1908) · Wikimedia Commons · Public domain (artist died 1908)
The Valley of Fear is the fourth and final Sherlock Holmes novel by British writer Arthur Conan Doyle. The backstory is loosely based on the Molly Maguires and Pinkerton agent James McParland. The story was first published in the Strand Magazine between September 1914 and May 1915. The first book edition was copyrighted in 1914, and it was first published by George H. Doran Company in New York on 27 February 1915, and illustrated by Arthur I. Keller.
Summary source: Wikipedia: The Valley of Fear · CC BY-SA 4.0