Sir Arthur Conan Doyle was both a doctor and a believer in spirits, which may partly explain why his Sherlock Holmes is one of literature's most beloved detectives: Holmes always approaches his cases with the gentility and logic of a scientist, but the stories are suffused with an aura of the supernatural. Narrated by devoted assistant Dr. John H. Watson, Holmes's adventures were so addictive that fans protested the master deducer's