The Spirit of the Liturgy by Joseph Cardinal Ratzinger is truly an amazing book. Here is a short sample: part of the conclusion to Chapter 3 and the conclusion to Part One.
"As we have seen, Christian liturgy is a liturgy of promise fulfilled, of a quest, the religious quest of human history, reaching its goal. But it remains a liturgy of hope. It, too, bears within it the mark of impermanence. The new Temple, not made by human hands, does exist, but it is also still under construction. The great gesture of embrace emanating from the Crucified has not yet reached its goal; it has only just begun. Christian liturgy is liturgy on the way, a liturgy of pilgrimage toward the transfiguration of the world, which will only take place when God is 'all in all'".
What a great summary of why I entered the Anglican Communion, and why I call "what I do" Quest Ministries.
If Ratzinger's statement seems meaningful but incomplete, you will want to pick up a copy of The Spirit of the Liturgy (http://www.amazon.com/Spirit-Liturgy-Joseph-Cardinal-Ratzinger/dp/0898707846/ref=sr_1_1?s=books&ie=UTF8&qid=1341400523&sr=1-1&keywords=The+Spirit+of+the+Liturgy) and read the whole book. I'm reading it again for the first time.