Behavioral Individuality in Early Childhood. By Alexander Thomas. Herbert G. Birch, Stella Chess, Margaret E. Hertzig, and Sam Korn. New York:  New York University Press, 1963.  xii + 135 pp.

The authors of this monograph are collaborating in a longitudinal study, in progress since 1956, of the “interplay of organismic and environmental forces in the development of the child.” Their research was designed to investigate separately each of these aspects of development, in order “to learn its laws,” and then to explore them in an integrated way and determine the interdependencies. Discussions of the project were published earlier in the periodical literature, but this is the first book-form report.

It devotes five chapters to general considerations and issues of research methodology and three chapters to findings. The latter are exclusively concerned with the organismic characteristics of the 80 children in the total sample of 130 who had passed their second birthday at the time these data were analyzed. The variability and persistence of their initial patterns of reactivity and the influence of these patterns on parent-child relations during the first two years of life are detailed. The methods of identifying and rating these temperamental characteristics are explained and illustrated in appendices containing material from parental interview protocols.

Most mothers discover through experience that infants differ in their patterns of reactivity, and that some are much easier to deal with than others. Many clinical investigators agree that whether die mothering is easy or difficult profoundly affects the mother's relationship with the