This book examines the concept of adaptation in four major fields in the human sciences. Genetic aspects are first considered through an examination of the human genes which have so far been identified as conferring survival value in particular environmental circumstances. The drift versus selection argument is also fully reviewed. The second contribution concerns the physiological changes which occur when individuals move from one environment to another. In the past, most attention has been given to the mechanisms of these changes, but here the focus is on the effects. The third contribution is directed at the analysis of behaviour - especially social behaviour. The application of kin selection and reciprocal attraction theories to humans is explored and the value of these approaches explained, whether the behaviour has a genetic basis or not. The final essay deals with the relevance of the adaptation concept to the social sciences and especially to social anthropology. It demonstrates that an ecological approach to understanding the nature and structure of human societies demands attention to adaptation.Reprinted in paperback for the first time and with a new foreword, this book, which serves as an excellent teaching text, clearly shows how attempts at integration in each of these various fields can benefit the study of human evolution, social structure and organization from all perspectives.