This yearbook contains 19 articles discussing current knowledge and concerns about youth from the ages of 15 through 25. Section I, dealing with youth as a stage of life, discusses the major themes and the implications of youth; sex differences in the opportunities, demands, and developments of youth; the physical and emotional health of youth; and the objectives of youth's self-development and social relations. Section II focuses on the psychological and social processes by which young people become adults in contemporary society. Specifically discussed are the psychohistory of protest leaders and followers; youth and the meaning of work; youth and experiential learning; sex, sex roles, and marriage among youth in the 1970s; and a generational analysis of youth in the 1970s. Section III emphasizes cultural pluralism and presents relevant data on youth in various subcultures including blacks, rural "WASP," Mexican Americans, Asian Americans, low income families, and women. An epilogue compares the study of youth that was presented in the 1944 yearbook with the study presented in this 1975 yearbook. The book also contains a subject index, background information on the National Society, and a list of the society's publications. (Author/RM)