This is the fifth volume of a detailed and systematic exposition of the history, canonical structure, doctrine, social and moral teaching, liturgical services, and spiritual life of the Orthodox Church. The purpose of this series is to present Orthodox Christianity as an integrated theological and liturgical system, in which all elements are interconnected. This has been the law of the Church from ancient times:
lex orandi, lex credendi
, "the law of prayer is the law of faith."