From a relational and evolutionary perspective on the mystery of vocation, the authors develop the principles of discernment for Christian marriage, celibacy, and singlehood. They see the vocational core of marriage as a calling by God of each spouse to be a unique instrument of transformation and purification in the other's spiritual journey. They identify the vocational core of celibacy as the relationship between Jesus and the celibate rendering the celibate unmarriageable for the sake of Christ and the Gospel. They view the vocational core of singlehood as witness to a certain independence for the sake of the reign of God. In the light of each vocational core, the authors discuss specific signs which indicate and authentic calling. This book appeals to those seeking to discern their personal vocation as well as to those guiding them.