The Hound of the Baskervilles

This is the Holmes novel most people mean when they say Sherlock Holmes. Conan Doyle wraps a rational detective story inside genuine Gothic atmosphere — the Dartmoor moors, an ancestral curse, a hound that seems supernatural — and lets Holmes work behind the scenes while Watson carries the suspense. The tension between reason and superstition, played out across a wild English landscape, is what makes it more than a puzzle. The one honest frustration is that Holmes disappears from the foreground for a large stretch; readers who want constant Sherlock presence may feel his absence. Period class attitudes are present but not central. Otherwise this is about as family-safe as classic fiction gets, and it has earned its reputation over more than a century of continuous readership.