This volume is an attempt to integrate the theory and data of social and personality development within a modem evolutionary framework. The various chapters are not meant to be read in isolation from one another but rather are intended to form an integrated whole. There is thus a great deal of cross-referencing between chapters and to some extent they all stand or fall together. This also suggests that the accuracy (or usefulness) of a particular chapter cannot be judged until the book is comprehended as a whole. Chapter 1 deals with the theoretical foundations of this enterprise, and the focus is on the compatibility of mainstream approaches within the field to a modem evolutionary approach. Chapters 2-4 concern what I view to be the fundamental proximal mechanisms underlying social and personality development. Chapter 2, on temperament and person­ ality development, is particularly central to the rest of the volume because these processes are repeatedly invoked as explanatory concepts at later points in the volume.