A widely-known Dutch theologian undertakes a critical study of the general movement popularly known as secularization, and finds both the term and the assumptions often attached to it open to question. He accepts temporarily certain current statements, e.g. that secularization is the historical process by which the world is desacralized, that secularization raises the question of who God is, and that secularization and God's plan of salvation have no common ground. Yet he rejects the two main interpretations of secularization: that it is fateful destiny (Nietzsche) or that it is a welcome ""end of an illusion"" (Bonhoeffer, Bultmann). He does not agree that it is an indisputable historical process, and he pursues this position by close examination of such branches of science as cosmological and biological systems, and the more humanistic fields of psychology, philosophy, history and theology. In opposition to the view that the Gospel must be made relevant in terms understandable to modern man, he replies that ""modern man's system of categories is thin and defective in the highest degree."" In the end, the ""saving activity of God from creation to consummation"" is the only adequate presuppositional basis even for modern science. A sharply reasoned, sometimes elliptically stated treatise, dealing astringently with many modern assumptions, in and out of the church.