Brazilian Spiritism (espiritismo, kardecismo) is an important middle-class religious movement whose followers believe in communication with the dead via spirit mediums and in healing illnesses by means of spiritual therapies. Unlike Anglo-Saxon Spiritualists, Brazilian Spiritists count among their number a well-developed and institutionalized intellectual elite that has reinterpreted northern hemisphere parapsychology and developed its own alternative medicine and sociology of religion. As a result, the mediation between popular religion (especially Afro-Brazilian religious practices) and the orthodoxies of the universities, the state, and the medical profession.

Situating Spiritist intellectual thought in what he calls a broader ideological arena, Hess examines Spiritism in the context of religion, science, political ideology, medicine, and even the social sciences. Hess challenges the legacy of French sociologist Roger Bastide, who saw in Spiritism an elitist, middle-class ideology. In the process, Spirits and Scientists provides a new approach to middle-class religious movements in Latin America.