The Panel Study of Income Dynamics (PSID) has collected data on the same families and their descendants for 39 waves over 47 years (as of 2015). In the 1990s, PSID began collecting rich and detailed data on children born into these families and, starting in the mid-2000s, has closely followed these children?s transition into adulthood. Young adults in PSID families become members of the Core PSID themselves and receive the full interview when they form their own economically-independent households?and are followed by the study for the rest of their lives. This Program Project will draw on, and contribute to, PSID data on the transition into adulthood within its life course and intergenerational family context through three projects and one core. The Program Project has three overarching aims. First, we will collect two waves of the PSID Transition into Adulthood Supplement (TAS) in 2017 and 2019. We will undertake a major expansion of the TAS study sample and will substantially revise the TAS questionnaire, adding new and revised content on topics such as childhood health, fertility-related behavior and pregnancy intentions, and computer skills. These new data will yield a life course panel of children from birth and preschool through primary and secondary school and then through entry into the world of work or higher education in conjunction with early family formation. The data are vital for our understanding of the contemporary transition from adolescence into adulthood in the U.S. within its intergenerational family context. Second, we will use these data to advance research on two topics of considerable scientific and policy significance: (a) the key factors shaping family formation processes in recent cohorts, and the effects of family background and childhood trajectories on these family formation processes; and (b) how childhood health trajectories, from birth through childhood and adolescence, affect socioeconomic status transitions in early adulthood, including educational attainment, employment, and residential and financial independence from parents. Our research findings will provide valuable new information about how and why lifecourse disparities in demographic, health, and socioeconomic status outcomes emerge during early adulthood; will reveal how these outcomes are transmitted across generations; and will uncover mechanisms that link family background and childhood lifecourse experiences with young adult outcomes. Third, we will document and distribute the new TAS data through the publicly available and free PSID Online Data Center and promote the use of the TAS data archive.