The fourth mail and personal interview followup survey from October 1979 to May 1980 is reported as part of the National Longitudinal Study of the High School Class of 1972 (NLS). The report is methodological, historical and descriptive in nature, but contains no analytical results. Reference to earlier reports is provided in determining post secondary educational and vocational activities of young adults in transition years. The six sections present the background and purpose of the NLS, an overview of operations, the development of the fourth followup instruments, related materials, and linkages between the fourth and prior followup questionnaire items. Data tables illustrate the text. (CM)