The book "Church and State in the Formation of Christianity", written by T. V. Allis, is a study of the relationship between the church and the state during the formation of Christianity as a system of beliefs in Europe. The author carefully examines the influence of the church hierarchy on the political decisions of that time, as well as the reaction of state institutions to church doctrines. In particular, the book examines the key events that contributed to the formation of the social and political system of Christian Europe. This is an interesting study for those interested in the interaction of church and state structures in the Middle Ages.