The essential forms of the liturgy were fixed very early according to the tradition received from the apostles. But the place given to biblical readings, teaching, singing, and ritual has varied through the centuries.

In History of the Liturgy, Metzger describes the most important phases of these changes. For the first millennium, he focuses on liturgy's essentials common to the Eastern and Western Churches. For the second millennium, he explains the deviations of the Western Churches which called for the effort of reform and renewal begun by Vatican II.

Metzger studies the development of the liturgical institutions and distinguishes liturgy's five main stages that correspond to the situations of the Churches in ancient, medieval, and modern societies.

This clear and accurate survey of the history of liturgy is designed to awaken readers' interest, on a solid yet introductory level, in the realities that have made and still make up the Church's liturgical life: assemblies, Eucharist, baptism, reconciliation, daily praise, the Church's calendar, and its architecture.