Today, readers revere Sir Arthur Conan Doyle as a master of the detective fiction genre. However, he had a life-long interest in the occult and the supernatural which long predated his creation of Sherlock Holmes, and many of his fiction and non-fiction works deal with these topics. In The Parasite, Conan Doyle explores the relationship between an exceedingly rational professor who succumbs to the charm of a beautiful clairvoyant and mesmerist -- and soon finds himself carrying out her nefarious directives against his will.