This is one of the Credo series of books in which renowned scholars and scientists spell out their philosophy or view of life which, it is hoped, will aid in clarifying the confusion about purposes now endured by men. The author, a distinguished biologist, holds that the problems of philosophy and religion are problems of life and, hence, of interest to a life scientist. Not surprisingly, Sinnott finds men at a turning point regarding beliefs and suggests that, to survive the crisis, all men must learn to get along together. The means of doing so, he feels, is agreement on a common religious philosophy. Recognizing that bridging the gap between materialists and followers of traditional religions will be difficult, Sinnott traces the development of man and body and spirit. He holds that the key to the common faith will be found in biological organization, in the two products of biological processes, individuality and the organization. Not an easy-reading book, it would be of interest to any person considering modern man's credo or his lack of faith. It stimulates thought while reaching no new startling conclusions.