This report describes patterns of continuity and change among spring 2004 high school seniors from the Education Longitudinal Study of 2002 (ELS:2002) first follow-up study, spring 1992 seniors from the National Education Longitudinal Study of 1988 (NELS:88) second follow-up study, spring 1980 seniors from the High School and Beyond (HS&B) base-year study, and spring 1972 seniors from the National Longitudinal Study of the High School Class of 1972 (NLS:72) base-year study. It supplies demographic profiles of 1972, 1980, 1992, and 2004 seniors and discusses their senior-year coursetaking and extracurricular activities, life values, educational expectations, and post-high school education and career plans. Chapter 1 describes changes in the racial/ethnic makeup of high school seniors from 1982 to 2004. Chapter 2 examines the courses taken by seniors during their senior year (in contrast to courses accumulated throughout their high school program, as examined in, for example, Bozick and Ingels 2008 and Dalton et al. 2007). During this last year of high school, seniors took higher-level courses in mathematics, science, and foreign language in greater proportions in 2004 than in 1982 (the first year for which coursetaking data are available). Seniors participated in a variety of extracurricular activities. The ones examined in chapter 3 are student government, honor society, athletics, newspaper or yearbook, vocational club, and academic club. There was both some overall change and a good deal of stability in the patterns of participation among seniors. Chapter 4 examines plans for work and school immediately after high school, as well as the importance of certain factors in choosing a postsecondary education institution. Plans for highest educational level and occupational attainment at age 30 are examined in chapter 5. Two appendixes include: Technical Notes and Glossary; and (2) Standard Error Tables. (Contains 38 tables, 4 figures, and 21 footnotes.) [This report updates an earlier NCES publication, "Trends among High School Seniors, 1972-1992" (ED387533).