The disruptive effects of disasters on societies and individuals have been described in written history, diaries, and autobiographical and legendary fictional accounts. The roots of disaster research can be found in the pioneering studies by A. Freud and Burlingham (1944) at the Hampstead war nurseries that brought attention to the problems experienced by young children who were forced to separate from their families during wartime. Their studies influenced subsequent research and clinical efforts to help children who were undergoing overwhelming stress, and provided the basis for Bowlby's landmark developmental theories of attachment, separation, and loss (1973). The pathbreaking work of Lindemann (1944); Bloch, Silber, and Perry (1956); and Wallace (1957) established the field of disaster research in the American social and behavioral sciences. Efforts to investigate disasters evolved out of community studies in the social sciences, including social psychology, sociology, and cultural anthropology. Because early disaster research stemmed from these community studies, it focused more on understanding the collective behavior of groups following a disaster. The study of the psychological effects of a disaster on individuals came later.