The proposed publication is dedicated to the rich and dramatic history of the Orthodox Churches of South-East Europe during the Second World War. This period became not only very important, but also the least studied in history, when, on the one hand, new non-canonical Orthodox Churches arose (Croatian, Hungarian), and on the other, some traditional ones (Serbian, Greek) were subjected to severe persecution. At the same time, a number of Local Churches exerted not only spiritual, but also political influence, significantly influencing the situation in their countries (Bulgaria, Greece, etc.). In a difficult military situation, a significant place was occupied by the relations of the Orthodox Churches of South-Eastern Europe with the Russian Church, to which special attention was paid in the work. In some countries, Russian church emigration during the war period played a decisive role in the development of Orthodoxy (Czech Republic, Slovakia, Hungary, Italy). The monograph is based on rich archival sources, in particular materials from German, Bulgarian, Serbian, Greek, American, Russian and other archives. The book is intended for historians, religious scholars, teachers and students of religious educational institutions, as well as for all readers interested in the history of Christianity. PDF A4 format saved publishing layout.