Since it is only in the present century that the actual contents of the Church's teaching on marriage have been formulated and since there has been a manifest reticence on the part of the magisterium about obtaining advice from theologians, Catholic marital theology is currently in a state of flux. The present work seeks to arrest this flux and determine exactly the present state of questions relating to marriage and their possible future outcome. In his treatment of natural law and sexual union, of sexual personalism, and of evangelical celibacy, the author writes with a serene objectivity which transcends all such facile classifications as conservative or progressive; that is, he writes as a theologian deeply conscious of the needs of e humanity which is evolving towards a greater and greater understanding of the Christ who is the same " yesterday, today, forever”.