Pius Parsch's The Liturgy of the Mass is a seminal work of the 20th-century liturgical movement aimed at enhancing Catholics' understanding and active participation in the Mass. It offers a thorough exploration of the history, structure, and theological significance of the Roman Catholic Mass, which at the time focused on the Tridentine Rite or Traditional Latin Mass. Parsch's central focus is tracing the historical development of the Mass, from its origins in Jewish ritual and the Agape meal to its form in the early Church and the Roman Mass of his day. He explains the theological significance of the Mass as a sacred meal, a living memorial of Christ's sacrifice on the cross. He restores the lay faithful's understanding of their role in the liturgy. He criticizes practices where the Mass becomes a private devotion of the priest while the people are passive, and emphasizes the need for the full, active, and conscious participation of the entire congregation. Overall, this book is a catechetical and spiritual guide designed to help the faithful connect more deeply with the divine mystery of the Eucharist and make it the center of their spiritual lives, rather than simply an external ceremony.