Spiritism is based on the five books of the Spiritist Codification written by French educator Hypolite Léon Denizard Rivail under the pseudonym Allan Kardec reporting séances in which he observed a series of phenomena that he attributed to incorporeal intelligence (spirits). His assumption of spirit communication was validated by many contemporaries, among them many scientists and philosophers who attended séances and studied the phenomena. His work was later extended by writers like Leon Denis, Arthur Conan Doyle, Camille Flammarion, Ernesto Bozzano, Chico Xavier, Divaldo Pereira Franco, Waldo Vieira, Johannes Greber and others.
Spiritism has adherents in many countries throughout the world, including Spain, United States, Canada, Japan, Germany, France, England, Argentina, Portugal and especially in American countries such as Cuba, Jamaica, and Brazil, which has among the largest proportion and greatest number of followers.
Spiritism had its background in the Spiritualist movement that emerged in the mid-19th century. In its broad sense, Spiritualism is any philosophical or religious movement that opposes materialism. In its narrower sense, it is any movement that believes that spirit entities exist and that human beings can engage in spirit communication and mediumship. Therefore, Spiritism is Spiritualist. Spiritualist Churches, however, differ from Spiritist groups in that Spiritualism as a religious denomination doesn't stress Reincarnation as a basic tenet of belief (some Spiritualists believe in Reincarnation and some don't, whereas Spiritists believe in Reincarnation as a basic tenet of their belief system).