Few realize that a person can pursue a truly supernatural vocation by consecrating himself or herself to perpetual celibacy while yet living in the world. Here Fr. Unger describes the main guidelines for such a religious vocation, showing the nature of this vocation and the manner of dedicating oneself to it. The author gives the history in the Church of consecrated celibate living, plus some basic helps in safeguarding purity in such a life. Based on the Pope Pius XII encyclical On Holy Virginity, this book shows that the consecrated life in the world is just one more example of the rich Tradition of the Church in providing for the needs of all her children. The Mystery of Love for the Single will bring much-needed encouragement and enlightenment to those generous souls who wish to pursue a supernatural vocation and yet remain single and celibate while living in the world.