This third edition has been revised to reflect new research findings and theories pertaining to the development and behavior of adolescents and to keep it n step with changing attitudes and social forces that influences the views and conduct of youth. A new chapter and new sections in other chapter deal with the following issues: 1) Changes in sexual mores and the impact of these changes on youth. 2) The consequences of increasingly strong demands for equality between the sexes, including revised ideas about masculinity and femininity and the effect such ideas might have on the self-image and vocational aspirations of boys and girls. 3) Drug use among adolescents, including the increasing use of alcohol in early and middle adolescence. 4) The problem of delinquency as seen from the points of view of the delinquents themselves and their apprehensive elders. 5) Militancy and social activism, notably at the college level.