A comprehensive introduction to the liturgy of the Roman Rite, set within a broader consideration of Christian liturgies Eastern and Western (Byzantine, Mozarabic, Ambrosian, and Reformed). The central theme of the book is the life-creating, even deifying, communication between God and human beings. Part 1 deals with God's invitation to humanity to enter the divine fullness of life. This is God's descent or "katabasis." Part 2 concerned with humanity's acceptance of the invitation-the human ascent to God or "anabasis." Following this extensive treatment of the general nature of Christian liturgy are four sections devoted to particular subjects: the celebration of the Eucharist, the celebration of the sacraments, the liturgy of the hours and other services of the Word, and, finally, the liturgical year.