The version in English of Zualdi's Sacred Ceremonies of Low Mass, by the late Rev. M. O'Callaghan, C.M., has been for years considered the standard worK for making up the Rites and Ceremonies of the Mass by Ecclesiastical Students and Priests alike. The promulgation, however, of the Code of Canon Law, and the appearance of the Typical Edition of the Roman Missal, especially the Additiones et Variationes appended to the Rubricae Generales and the Ritus, have called for a certain number of changes in this New Edition. But my aim has been to make only necessary changes. I verified, with the help of others, all the instructions in the old edition, and kept the same expression of them as heretofore, whenever I could. Numbers of these instructions have now even more authority than they had previously. The august Sacrifice of the Mass comprises in itself all that is most sublime and sacred in our Holy Religion. All the sacrifices of the Old Testament were only shadows of that of the new, which, as St. Leo says, really offers to God what the Jewish sacrifices only promised. The offering should bear some proportion to the person to whom it is made; but since the ancient sacrifices were only weak and needy elements, they could in no way satisfy for man's debts to God and hence another sacrifice was required. The old victims were insufficient, the Levitical priesthood was impotent in the sight of God, therefore it was necessary, as the Fathers of the Council of Trent express it, that by the ordination of God the Father of Mercies, another Priest, according to the order of Melchisedech, our Lord Jesus Christ, should arise, who would consummate and bring to perfection all who were to be sanctified. Although Our Lord fully consummated the sacrifice by offering Himself to God the Father, and by dying on the altar of the Cross for our redemption yet His priesthood was not to expire with His death, but was to continue visible in His Church to the -end of ages, as He Himself promised at His Last Supper when, instituting the. Eucharistic Sacrifice, He gave the same Divine authority to the Apostles, and to their successors. Every Priest can, therefore, say to himself when ascending the altar: I am no longer a mere man of clay, a weak creature-being identified with Jesus Christ throogh the power and the infinite value of the Victim I am about to offer. With what a high degree of virtue; ought such a dignity be accompanied!