The author's concern here is with the experiential forms and contents of faith in the situation in which modern man must find himself and his way of dealing with the power that has become his. Modern man is ""radial man"" -- symbolized by the radio listener -- for whom the immediate reality is power, and for whom the prime question is the method or style he employs to assimilate it. Faith and doubt become, not an opposition between belief and disbelief, as for earlier man, but aspects or modes through which radial man tries to respond both to the affirmations of faith, and the wide but positive significances of human experiences outside the categories of traditional faith. Professor Niebuhr aims at showing how men today can take the ways and issues of religion and faith and God, as understood heretofore, and see them under the new light thrown upon the new man of today, who must live in a world where power is always disturbing and, at the same time, reshaping him. Niebuhr uses both scholarship and personal testimony so that the reader, at a loss with traditional theological issues, always finds points of references which obtain to the common experience of ordinary men. The book should have impact on current theological discussion and prove personally helpful to a broader audience.