A set of three studies focused primarily on an indepth analysis of the National Longitudinal Survey ("Parnes") data tapes, concentrating particularly on the experience of young men and young women, but collating them also with data on experience and background of other family members available in the parallel surveys. Research was conducted in three major areas (presented in the three separate papers included): (1) The effects of schooling interruption and work while in school on subsequent educational and economic success of individuals (The ability-schooling-income relations were analyzed using data on families); (2) re-examination of estimates of returns to schooling and the effect of controlling for ability on them; and (3) the changing economic market for college graduates and its impact on the individual returns to education and the educational system as a whole, and its effect on traditional black/white differences in socioeconomic attainment. Some major implications of the research follow: (1) College training may no longer be as valuable an investment in human capital as in years past, suggesting more emphasis on other forms of vocational training, (2) the role of learning by experience or on-the-job training suggests the need for substantial work on the "actual" way in which human capital accumulation occurs and the possible tools for influencing it, and (3) given the current state of knowledge and data on the economic success of individuals, neither family background nor measured ability account for a major portion of the observed variance in the economic success of individuals. (TA)