This book is especially designed for the instruction of novices who sincerely desire to enter a religious community. It may be read with much fruit by all those who wish to lead exemplary lives. It is supposed that when you begin to peruse this Manual, you'do so through an earnest desire of advancing in virtue. We take it also for granted that you are convinced of the expediency of choosing the state of life which God has destined for you at your birth, because He attaches to it special help and graces. For men there are three states to which a special vocation is attached: the priesthood, the religious state in a community approved by the Church, and the lay state, Women are called only to the two last named. In the lay state there are the state of marriage and the state of virginity. The latter is in itself more perfect than the former but not for all, for to some the words of St. Paul may be applied, that "It is better to marry than to burn." Although this volume may be read with fruit by priests who are in charge of religious communities and by all those who wish to live holy lives, it is mainly intended for the instruction of postulants and novices, who desire to embrace the religious state, whether in a contemplative order or in an active religious institute, for the practical lessons are particularly applicable to them. St. Thomas teaches without the least hesitation that the essence of Christian perfection consists primarily in the love of God, and secondarily, in the love of neighbor for God's sake. There is then a perfection that we can attain in this world, a true perfection, which is a perfection according to man's nature, aided by God's grace, .and it is this perfection or charity to which we should all aspire according to the words of St. Paul: "Have before all charity which is the bond of perfection," as if he said, strive to possess the virtue of charity, which unites all the virtues into one homogeneous whole, and in that, perfection consists. Again the same Apostle says: "Love therefore is the fulfilling of the law," for he that loves God and his neighbor fulfills all that God has commanded, according to the Savior's words: "Thou shalt love the Lord, thy God. and thy neighbor as thyself. On these two Commandments dependeth the whole law and the prophets."