Considered by Ratzinger devotees as his greatest work on the Liturgy, this profound and beautifully written treatment of the great prayer of the Church will help readers rediscover the Liturgy in all its hidden spiritual wealth and transcendent grandeur as the very center of our Christian life. In his own foreward to the book, Cardinal Ratzinger compares this work to a much earlier classic of the same title by Romano Guardini because Ratzinger feels that his insights here are similar with what Guardini achieved in his time regarding a renewed understanding of the Liturgy. My purpose here is to assist this renewal of understanding of the Liturgy. Its basic intentions coincide with what Guardini wanted to achieve. The only difference is that I have had to translate what Guardini did at the end of the First World War, in a totally different historical situation, into the context of our present-day questions, hopes and dangers. Like Guardini, I am not attempting to involve myself with scholarly discussion and research. I am simply offering an aid to the understanding of the faith and to the right way to give the faith its central form of expression in the Liturgy.