'Although biologists typically treat change and constancy as independent, polar opposites, Bateson and Gluckman argue forcefully that they actually are - like yin and yang - interwoven and mutually interdependent. Their carefully constructed, systematic, and balanced new book provides a much-needed roadmap that guides the reader through the intricacies of development and its interplay with evolution.' Mark S. Blumberg, F. Wendell Miller Professor of Psychology, University of Iowa and author of Freaks of Nature: What Anomalies Tell Us About Development and Evolution