This is a fifteen volume set, which is being brought back into print for the edification of the Faithful. Anyone who wishes to appreciate the timeless Tridentine Mass and liturgy will find this set a valuable aid in that endeavor. Dom Gueranger has produced a most excellent work, which began the liturgical movement. We pray that this set of books will bring many more to a true appreciation of the Latin Mass and the Divine Office of the Catholic Church. At one time, under the impulse of that Spirit, which animated the admirable Psalmist and the Prophets, she takes the subject of her canticles from the Books of the Old Testament; at another, showing herself to be the daughter and sister of the holy Apostles, she intones the canticles written in the Books of the New Covenant; and finally, remembering that she, too, has had given to her the trumpet and harp, she at times gives way to the Spirit which animates her, and sings her own new canticle. From these three sources comes the divine element which we call the Liturgy. The Prayer of the Church is, therefore, the most pleasing to the ear and heart of God, and therefore the most efficacious of all prayers. Happy, then, is he who prays with the Church, and unites his own petitions with those of this Spouse, who is so dear to her Lord, that he gives her all she asks. It was for this reason that our Blessed Saviour taught us to say our Father, and not my Father; give us, forgive us, deliver us, and not give me, forgive me, deliver me. Hence, we find that, for upwards of a thousand years, the Church, who prays in her temples seven times in the day, and once again during the night, did not pray alone. The people kept her company, and fed themselves with delight on the manna which is hidden under the words and mysteries of the divine Liturgy. Thus initiated into the sacred Cycle of the mysteries of the Christian year, the faithful, attentive to the teachings of the Spirit, came to know the secrets of eternal life; and, without any further preparation, a Christian was not unfrequently chosen by the Bishops to be a Priest, or even a Bishop, that he might go and pour out on the people the treasures of wisdom and love, which he had drunk in at the very fountain-head. For whilst Prayer said in union with the Church is the light of the understanding, it is the fire of divine love for the heart. The Christian soul neither needs nor wishes to avoid the company of the Church, when she would converse with God, and praise his greatness and his mercy. She knows that the companyof the Spouse of Christ could not be a distraction to her. Is not the soul herself a part of this Church, which is the Spouse? Has not Jesus Christ said: Father, may they be one, as we also are one? and, when many are gathered in his name, does not this same Saviour assure us that he is in the midst of them? The soul, therefore, may converse freely with her God, who tells her that he is so near her; she may sing praise, as David did, in the sight of the Angels, whose eternal prayer blends with the prayer which the Church utters in time.