Studies the secular institutes from an historical, theological and juridical viewpoint. In so doing, the author clarifies the differences between the lay secular vocation and the religious life. The secular institutes undertake those duties of charity which religious orders are unable to carry out. Their members do not usually live in common, but come together for the sacraments and spiritual conferences. Generally, the institutes are made up of laymen who must take at least one vow (or promise), usually that of perpetual chastity.