This text discusses the principles behind the limits of papal authority over the liturgy, with an emphasis on the documents of the ecumenical councils, papal documents, saints and theologians throughout history. The book provides an initial look at the role of Divine, Divino-Apostolic and Apostolic tradition in relation to the liturgy, as well as the the principle of longevity and the role of the Natural Law and the Divine Positive Law in determining when the pope can make liturgical changes or suppress a rite.