In the year 1900, Sir Arthur Conan Doyle was at the height of his success as a doctor, a sportsman, a writer of historical novels, a champion of the oppressed and, most notably, the creator of that honourable, brave and eminently sensible master detective, Sherlock Holmes. Every new Holmes story was greeted with great anticipation and confidence in the knowledge that, however complex the crime, the supremely intelligent and logical detective would solve it. But in 1916, Conan Doyle suprised his readers by declaring that he believed in spiritualism. And, when, in 1922, he published a book in which he professed to believe in fairies, his devotees were distinctly unimpressed. How could the man who invented ultra-rational Holmes claim to believe in something as bizarre and unproven as the paranormal? Andrew Norman delves into both Doyle's medical records and his writings to unravel the mystery of his beliefs, and to provide an unusual perspective on the life of the man behind Sherlock Holmes.