The topic of the publication directly concerns problems that are extremely relevant for world Orthodoxy: primacy in the Universal Church, the Orthodox diaspora, the diptych, autocephaly and methods of its proclamation. The book is the first to attempt a detailed study of the development of the doctrine of the primacy of the bishop in the works of Russian Orthodox theologians belonging to different jurisdictional directions, and official documents of the Russian Orthodox Church of the 20th century, and conducts a comprehensive analysis of it. The issue is considered in the context of the historical and political conditions in which Russian Orthodox theologians found themselves in different church jurisdictions. The development of the doctrine of the primacy of the bishop in Russian Orthodox theology is compared with the ecclesiological reform and the doctrine of primacy in the Roman Catholic Church in the 20th century, and the issue of mutual influence and intersection of the Russian Orthodox and Catholic traditions is explored. The book will be useful to everyone who is interested in Russian Orthodoxy, the history of the Church, issues of canonical church structure, church law, church-state and inter-Orthodox relations, Orthodox-Catholic theological dialogue.