"The Boscombe Valley Mystery", one of the 56 short Sherlock Holmes stories written by the British author Sir Arthur Conan Doyle, is the fourth of the twelve stories in The Adventures of Sherlock Holmes. It was first published in the Strand Magazine in 1891. Lestrade summons Holmes to a community in Herefordshire, where a local landowner has been murdered outdoors. The deceased's estranged son is strongly implicated. Holmes quickly determines that a mysterious third man may be responsible for the crime, unraveling a thread involving a secret criminal past, thwarted love, and blackmail. Sherlock Holmes and Dr Watson take a train to Boscombe Valley, in Herefordshire. En route, Holmes reads the news and briefs Watson on their new case.

Sir Arthur Ignatius Conan Doyle (May 22, 1859 – July 7, 1930) was a British author most noted for his stories about the detective Sherlock Holmes, which are generally considered a major innovation in the field of crime fiction, and for the adventures of Professor Challenger. He was a prolific writer whose other works include science fiction stories, historical novels, plays and romances, poetry, and non-fiction.