A historical and theological guide that examines the background, doctrines, and traditions of various Eastern Christian denominations that separated from the Roman Catholic Church. This book focuses on Christian communities that do not recognize the authority of the Pope in Rome. The author examines two major groups of major schisms in Church history: the Eastern Orthodox Church, including the communion of churches (such as the Greek, Russian, and Serbian Orthodox) that split as a result of the East-West Schism of 1054; and the Oriental Orthodox Church, including the group of non-Chalcedonian churches that rejected the decisions of the Council of Chalcedon in 451 AD, including the Coptic Church (Egypt), Syriac Orthodox (Syria/India), Armenian Orthodox, and Ethiopian Orthodox. This book serves as an encyclopedic survey covering key aspects of each tradition, such as (a) History (the background of how and why these groups separated and developed independently from the West), (b) Liturgy & Ritual (an in-depth description of each church's worship style, rites, music, and sacred art), (c) Theology (an explanation of the doctrinal points that distinguish these churches from each other and from Western Christianity) and (d) Ecclesiastical Organization (leadership and hierarchical structures, including the positions of Patriarchs and Bishoprics). This book provides cross-cultural insights that are essential for ecumenism and the study of the history of religions.