The present book, originally published in French, and now in English with a new foreword by Dom Alcuin Reid OSB, is a splendid example ante litteram of the task of the Hermeneutic of Continuity so courageously undertaken by Pope Benedict XVI. Without calling for a change in the post-Conciliar discipline of the Latin Church, the author offers a complete and trenchant historical and dogmatic critique of the recent neglect of the individually celebrated Mass in favour of concelebration. The discipline of the church after Sacrosanctum Concilium, up until the 1982 Code of Canon Law and the General Instruction of the Roman Missal for the third edition of the Missal of Paul VI, has always asserted the freedom of priests to celebrate individually, yet the liturgical and theological atmosphere of seminaries and religious communities has rarely favoured this freedom. Here is a careful discussion of the value of the multiplication of celebrations of the Eucharist, in the light both of the nature of the Eucharistic Sacrifice itself and of the theology of its fruits. A meticulous study of the history of the practice of concelebration shows that the present practice of daily concelebration, especially among simple priests without their Ordinary presiding, far from being a return to an ancient norm, is in fact a new development. The author concludes with a carefully nuanced set of practical proposals which, while giving to concelebration its due place, would serve to make better use of the infinite riches contained in the Holy Sacrifice. This conclusion may be summed up by the ancient prayer over the gifts found in both forms of the Roman Mass and quoted in the Constitution on the Sacred Liturgy of the Second Vatican Council: As often as the memorial of this Victim is celebrated, the work of our redemption is accomplished. May the careful examination of this beautifully reasoned study lead to a renewed sense of the efficacy of the Church's Offering and of its frequent and devout celebration by her priests.