"The History of Spiritualism, Vol. II" is a book by Sir Arthur Conan Doyle, most famous for stories about the brilliant detective Sherlock Holmes. Doyle had a wide sphere of interests, including spiritual phenomena and life after death. This book is a detailed account of how spiritualism developed historically until the beginning of the 20th century.

A young writer travels to Maine to tell the unusual story of America’s longest-running camp devoted to mysticism and the world beyond. They believed they would live forever. So begins Mira Ptacin’s haunting account of the women of Camp Etna—an otherworldly community in the woods of Maine that has, since 1876, played host to generations of Spiritualists and mediums dedicated to preserving the links between the mortal realm and the afterlife. Beginning her narrative in 1848 with two sisters who claimed they could speak to the dead, Ptacin reveals how Spiritualism first blossomed into a national practice during the Civil War, yet continues—even thrives—to this very day. Immersing herself in this community and its practices—from ghost hunting to releasing trapped spirits to water witching— Ptacin sheds new light on our ongoing struggle with faith, uncertainty, and mortality. Blending memoir, ethnography, and investigative reportage, The In-Betweens offers a vital portrait of Camp Etna and its enduring hold on a modern culture that remains as starved for a deeper sense of connection and otherworldliness as ever.

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.