Of Joseph Ratzinger’s three great works – The Spirit of the Liturgy , Introduction to Christianity , and Jesus of Nazareth  – the first is by far the most influential. Now in its twentieth year, we can take measure of The Spirit of the Liturgy’s impact on the life of the Church. There is much to measure.
In the book’s preface, Ratzinger announced his ambition for his work. He deliberately borrowed his title from Romano Guardini, whose book of the same name made a “decisive” contribution to Germany’s Liturgical Movement 82 years earlier. Ratzinger sought a “renewal of understanding” of the liturgy after Vatican II so as “to encourage, in a new way, something like a ‘liturgical movement,’ a movement toward the liturgy and toward the right way of celebrating the liturgy, inwardly and outwardly.”
At the time, there was no mystery why Ratzinger had this goal: for decades he had criticized the excesses of the post-conciliar liturgy, which, “by various restorations and reconstructions. . .threatened with destruction” the Mass itself. Ratzinger principally focused on abuses in the Novus Ordo Missae’s celebration rather than its theological intricacies. He began by inviting us away from debating the particulars and back to the very heart of liturgical worship, from which the particulars derive. The liturgy calls for worship in “spirit and truth,” words that “must not be taken in the subjectivist sense. . . .No, they must be seen in light of him who could say of himself, ‘I am the truth.’”
For Ratzinger, the core problem with the Novus Ordo was its subjectivist tilt away from glorifying God to glorifying His people. His first chapter, “Liturgy and Life” (which signals his broad perspective), famously located the apostasy of the Israelites around the golden calf: “Worship becomes a feast that the community gives itself, a festival of self-affirmation. Instead of being a worship of God, it becomes a circle closed in on itself.”
The comparison to the manner in which the liturgy has been celebrated since Vatican II is not subtle.
By contrast, the true spirit of the liturgy is revealed to us by God, not initiated from human creativity. Authentic human worship is cosmic; it brings the Son to us and us to God. The “goal of worship” is not self-affirmation, but “divinization,” and “all worship is a participation in this ‘Pasch’ of Christ.” The particular questions that Ratzinger subsequently addresses – active participation by the faithful, the building of churches, the altar and the direction of liturgical prayer, sacred music and art – are treated in service to this deeper purpose of liturgical worship. Or at least they are supposed to be.
The Spirit of the Liturgy received unprecedented publicity when Ratzinger became Benedict XVI in 2005. By the way he offered Mass in Christendom’s greatest basilicas, Ratzinger was able to manifest to the world the true spirit of the liturgy. Many noticed. Most important among them were the legions of young seminarians and priests devoted to God-centered liturgy, who found a new champion in Benedict.
Through the use of beautiful vestments and the recovery of discarded liturgical traditions, papal Masses became pious occasions for authentic worship of God. But Ratzinger gave the liturgical movement its greatest boost through Summorum Pontificum  (2007), which lifted restrictions on the use of the traditional Latin Mass. He desired “the two forms of the Roman rite” to be “mutually enriching,” and hoped the older rite would help the newer find “sacrality” and fidelity to its rubrics.
Ratzinger couldn’t have foreseen this twenty years ago, but the traditional Latin Mass has become the primary means whereby the message of The Spirit of the Liturgy is being spread the world over. Ironically, the book does not intentionally promote this form of the Mass.
Here is a short, incomplete list of the direct fruits of The Spirit of the Liturgy:
* The New Liturgical Movement  website devoted to studying and promoting the liturgy and the liturgical arts in their full, God-directed splendor.
* A growing drumbeat to return to celebrating Mass “ad orientem” – with priest and people together facing East – and away from the post-conciliar arrangement that turns the priest toward the people, a posture that especially facilitates the subjectivist, people-focused liturgy that Ratzinger decried. The chapter on this topic alone inspired one book ; and the “Benedictine altar arrangement” of a crucifix and six candles on altars to begin a gradual “reorientation” while the priest still faces the people, and (of course) loads of controversy.
* An explosion of books, conferences, and sacred music institutes dedicated to aspects of the liturgy mentioned by Ratzinger.
* The founding of the Benedict XVI Institute for Sacred Music and Divine Worship , which sponsored the recent traditional Mass of the Americas  at the National Shrine in Washington, D.C., something unthinkable without Ratzinger’s book and papacy.
For all these triumphs, The Spirit of the Liturgy has so far only affected a tiny pocket of the Church: the vast majority of parishes, schools, and religious orders still conduct their liturgies in the failed, people-centered manner. Moreover, numerous bishops and seminary formators still resist Ratzinger’s vision, especially the traditional Latin Mass.
Long before he wrote The Spirit of the Liturgy, Ratzinger famously predicted  that the Church would shrink but eventually be purified, so that “she will enjoy a fresh blossoming and be seen as man’s home, where he will find life and hope beyond death.” Currently, the “smaller, purer” Church is very often found at the traditional Latin Mass, which large families and other serious Catholics seek out for a reverent, God-centered liturgy.
The Mass beautifully offered to God, as described by Ratzinger, is the soil from which the fresh blossoming will spring. If we keep The Spirit of the Liturgy as our chartering work for twenty more years, the Church’s purification will bear greater fruit still.