The book was written on the base of materials collected by the author himself, both in his field ethnographic expeditions and as a result of his work in regional archives. In six chapters of the book, preceded with a general survey of Siberian peoples, there are the following central topics: belief in spirits and Shamanism, Lamaism (northern Buddhism), Islam, and Christianity (Orthodoxy). The chapters on the role of Christianity in the colonial policy of the pre-revolutionary Russia and the activities of officials, as well as the peculiarities of the missionary practice of Orthodox missionaries during the period of Christianization and Russification of Siberia are of particular interest. The book is completed with illustrations.