The four Sherlock Holmes novels form the structural backbone of the canon, introducing the universe's central characters and establishing its most substantial plots. A Study in Scarlet presents the first meeting of Holmes and Watson and sets out the consulting detective's method in full; The Sign of the Four deepens their partnership while introducing the case that leads to Watson's marriage; The Hound of the Baskervilles, the most celebrated and self-contained of the four, sends Holmes and Watson to the Devon moors for the canon's most atmospheric investigation; and The Valley of Fear, the final novel, returns to the theme of organised crime and secret societies that runs through the earlier work. The novels reward reading in publication order but The Hound of the Baskervilles functions as a natural entry point for newcomers encountering Holmes for the first time.