The modern liturgical movement owes a great debt to Solesmes monk Dom Eug ne Cardine (1905-1988), whose tireless research in the ancient manuscripts uncovered the elusive secrets of Gregorian Rhythm, thus revealing some of the original pristine beauty of Gregorian chant. In this volume, Dom Cardine sums up the origin, decline, and restoration of the chant, and challenges researchers to continue his work.