When Father Joseph Jungmann, S.J., rose to speak at the great International Congress of Pastoral Liturgy at Assisi in September 1956 he was greeted by applause so loud and so long that even a cardinalatial chairman could scarcely bring it to an end. It was the spontaneous recognition, by two thousand delegates from all over the world, of the special place that Father Jungmann holds not only among liturgical scholars but among all who have worked for the liturgical revival of our time. His subject at Assisi was ‘Pastoral Care: The Key to Liturgical History’, and it summed up his own achievement, which has been to apply the resources of an exact and unflagging scholarship to liturgical history but always so as to preserve a lively sense of its true purpose. At Assisi he compared the Liturgy to a tree: ‘if it has developed in the changing climate of the world’s history, if it has known times of storm and times of fruitfulness, nevertheless its growth has come from within and from vital forces which it manifests. The Liturgy is the life of the Church in the sight of God, of the Church which is the community of all those who are incorporated in Christ by baptism and who, Sunday by Sunday, gather to celebrate, under the direction of the priestly ministry, the memorial of the Lord.’