Today, Sir Arthur Conan Doyle's name is synonymous with detective fiction, and, most notably, the indelible character of Sherlock Holmes, with the master investigator and savant who was Conan Doyle's most memorable fictional creation. However, the author was also a leading figure in the Spiritualism movement and was regarded as one of the most important mystical thinkers of his era. This volume details Holmes' belief in the possibility of communication between the spirit world and our own realm.