Since 2007, use of the Roman Missal of 1962 has been broadly permitted within the church. This creates, in effect, two liturgical years running concurrently. In Advent to Pentecost, Abbot Patrick Regan compares the prayers and prefaces, readings and rubrics, calendar and chants of the 1962 Missal with those of the Missal as it was revised following the Second Vatican Council, now in its third edition. The result is a striking demonstration...