An early visual mass medium, the magic lantern was omnipresent in most Western societies between 1880 and 1930. The Christian Church, especially the Catholics, spiritual associations such as the Freemasons, political interest groups and teaching institutions all made use of lectures enriched by projected images to disseminate information, convictions and doctrines. Moreover, the lantern often featured as a concealed aid in stage spectacles. Nineteen authors analyse the effects of "the beam of light in the dark" in the context of religion, faith and belief. Attention is paid to the wide spectrum of locations where projections took place, as well as to the lantern's impressive versatility. The lavishly illustrated chapters collected in this volume range from analyses of religious propaganda to fundraising lectures for missionary work in China, from the fight against alcoholism to the secularisation of society, and from the lantern's application in spiritualist sessions to its use in science and teaching.