The book examines theoretical issues reflecting ecclesiological, canonical and socio-psychological aspects of the phenomenon of church schisms. The presentation of the material is based on the author's classification of possible forms of rupture in the unity of the Orthodox Church, taking into account the specifics and internal patterns of development of a splitting conflict. A canonical assessment of the issue involves an analysis of possible situations related to deviation into schism, staying in schism and the reunification of schismatics with the Church. The publication is recommended for students and teachers of theological educational institutions, clergy, religious scholars, as well as everyone interested in the issues of church schisms. The publisher's edition is saved in PDF A4 format layout of the book.