Plasticity of Development brings together innovative, current research by Jerome Kagan, Stephen Suomi, Sandra Scarr, Patricia Kuhl, Peter Mader, and Pasko Rakic on the nature/nurture issue, and presents new comparative approaches to epigenetic processes processes in which environmental signals act upon the genome - from the fields of child psychology, animal learning, brain development, and psycholinguistics. The studies address important issues concerning continuity of developmental processes, the nature of biological and environmental signals controlling epigenetic mechanisms, and the adaptive significance of developmental pathwaysAn introduction discusses theories of self-organizing systems including the important concept of canalization, which is taken up in chapters by Mader, Rakic, Kagan, and Suomi. Central to the study of development, canalization encompasses the idea that genetic information supports a self-organizing process that is guided by environmental input but that also provides a set of buffers against abnormal environmental and even genetic information.Kagan and Suomi describe continuity in developmental processes in humans and in Rhesus monkeys, revealing that in at least one important personality characteristic, response to challenge and stress, the behaviors and physiological correlates are strikingly similar. Scarr investigates the role of adoption and home environment on developmental continuity and shows that to a surprising extent children create the environmental niches they fill.Kuhl provides additional insight into the nature of the biological and environmental signals controlling epigenetic programs through her work on the development of speech perception in human children. The issue she raises of what is general and what is special in human speech perception and language development bears directly on the "open" versus "closed" teaming systems observed by Mader for oscine songbirds. In the most detailed account of the biological and environmental signals controlling epigenesis, Pasko Rakic describes the ontogenetic processes that produce the primate cerebral cortex.Steven Brauth, William S. Hall, and Robert J. Dooling are Professors of Psychology at the University of Maryland, College Park.