This relevant and influential book is the analysis of a longitudinal study of eighty-nine individuals who were assessed at birth and again at regular intervals; observational, psychometric, and interview data were collected for each child and his family until the child reached adolescence, and seventy-one of the subjects were reassessed when they became adults. The book emphasizes the relationship between early experiences and adult characteristics, and has remained throughout the years a forceful argument for and illustration of the continuity thesis.