A highly influential work of Christian theology and liturgical thought by Romano Guardini. First published in 1918, the book explores the meaning, purpose, and spiritual significance of the liturgy in Christian worship.

Guardini argues that liturgy is more than a set of rituals; it is a communal participation in the worship of God that shapes the spiritual life of believers. He examines themes such as prayer, symbolism, sacred space, sacrifice, beauty, and the relationship between individual devotion and communal worship.

The book had a profound impact on the twentieth-century Liturgical Movement and influenced later developments in the Catholic Church, including ideas associated with the Second Vatican Council.