Dr. Dubos' work as a microbiologist and his philosophical writings have always stressed the importance of studying interactions -- the dynamic interplay -- whether between microbe and cell, or man and society. He was an ecologist long before the word assumed its present vogue. In this work he expresses concern for the future of man given the pressures of population, pollution, and the meaningless or harmful detritus of an over ""technicized"" society. These forces work against the uniqeness of the individual and there is a real danger that man's social evolution could be altered by powers of selection which favor individuals more easily regimented, more noise-and smell-proof. Dr. Dubos sympathizes with today's youthful rebels but argues for a positive program: let science apply its techniques and methods to studying the shapes of space, the needs of sensitive man; find out which are the ingredients of the environment most harmful or destructive; which can be encouraged both pre- and post-natally to bring about the fullest expression of man's personal uniqueness and freedom. The range of Dubos' references -- Charles Abrams or Jane Jacobs on one page, Martin Bub or Jack London on another -- and his felicity of style make for pleasurable and stimulating reading.