A Study in Scarlet (1887)The very first Sherlock Holmes story. Dr. John Watson, newly returned from war in Afghanistan, meets Sherlock Holmes and becomes his flatmate at 221B Baker Street. Together, they investigate a strange murder in London that leads to a backstory set in the American West..The Sign of Four (1890)A tale of treasure, betrayal, and revenge. Holmes and Watson are hired by Mary Morstan, whose father mysteriously disappeared. The case involves a secret pact among four convicts, a missing treasure, and a dramatic chase across the Thames..The Hound of the Baskervilles (1902)Perhaps the most famous Holmes novel. Holmes and Watson investigate the legend of a demonic hound said to haunt the Baskerville family in Devonshire. A mix of Gothic atmosphere, suspense, and clever deduction..The Valley of Fear (1915)Holmes receives a coded message warning of danger, leading him into the murder of a country gentleman. The story connects to a secret American society, blending crime in England with a dark tale of violence in the United States.