On July 7, 2007, Pope Benedict XVI issued his long awaited motu proprio, Summorum Pontificum. In this document he granted permission "to celebrate Mass following the typical edition of the Roman Missal promulgated by Bl. John XXIII in 1962 as an extraordinary form of the Liturgy of the Church." Because of this motu proprio, there has been much interest in viewing the Paul VI missal as a continuation of the Bl. John XXIII missal. Understanding the earlier ritual expression is essential if we are to deeply understand the ordinary expression of the Mass of Paul VI. This book is a collection essays from the proceedings of the 11th International CIEL (International Centre for Liturgical Studies) Colloquium held at Merton College, Oxford, September of 2006. CIEL is an academic school of Liturgy founded in 1994 in Paris to form an academic school to instruct priests, seminarians, religious and the laity in the riches of Catholic liturgical history and development of the liturgy.