When first published in the 1920s, von Hildebrand's book revolutionized the dominant view of sexuality in the church, which was almost 2000 years old and often negativistic and puritan. In the ensuing decades, his writing has opened the eyes of countless young people to the depth, seriousness, and beauty of human sexuality as mystery and fulfillment of spousal love -- and to the sinfulness of anything that desecrates this mystery.