2018 Reprint of 1931 Edition. When this little book first appeared, it immediately brought wide recognition to a young theologian who would become an important force in the renewal of theology in the twentieth century. Originally written in 1918, this profound reflection on the nature of liturgical worship still stands as a guiding light for today's renewal of worship and prayer. In limpid, even poetic terms, it clarifies the underlying principles and existential implications of the belief that when Christians join in the Eucharist and other liturgical celebrations, they do so not as discrete individuals but as interconnected members of the one People of God.