Arthur Conan Doyle discusses how the spiritualism movement began and grew, and how he himself came to believe that talking with the spirits of the deceased was possible. The core tenet of spiritualism is the belief that the spirits of the deceased can communicate with the living. In order to establish contact, a person can attend a seance, or privately consult the services of a spiritualist medium. Mediums are persons deemed consistently able to attain communication with spirits, and receive messages from the spirit realm. Doyle's history recounts a number of incidents and people pertaining to spiritualism, and the growth of interest over the years. Many of the events date to the 19th and early 20th centuries, and Doyle quotes various testimonies in support of spirit manifestations. The behaviors and messages of spirits are described, while the author's own personal journey toward adherence is likewise alluded to.