As Mary Coredemptrix leads us to participate ever more deeply in the Eucharistic Sacrifice of her Son, may She also enable the Church to enter more lovingly into the daily commemoration of the many feast days in the Liturgical Year: " . . . these devotions should be so drawn up that they harmonize with the liturgical seasons, accord with the sacred liturgy, are in sane fashion derived from it, and lead the people to it..." (Constitution on the Sacred Liturgy, "Sacrosanctum Concilium," 13.) In presenting a brief history of hymns from the earliest monastic offices through such well-known sequences as the "Lauda Sion," "Veni Sancte, Spiritus" and "Stabat Mater," it is hoped that the present, new sequences may also inspire deep love for Christ and Our Lady, thus combining deep faith with devotion. The 137 sequences may be sung to Gregorian Chant melodies--the "Stabat Mater," "Lauda Sion" and "Dies Irae" in the Liber Usualis. It is ardently anticipated that the Maternal Mediation of Mary as Coredemptrix, Mediatrix and Advocate be solemnly defined as the fifth and final Marian Dogma of the Roman Catholic Church, ushering in the great Triumph of the Immaculate Heart of Mary.