This report presents findings from the base year of the Education Longitudinal Study of 2002 (ELS:2002), a new longitudinal study of high school students. The report provides descriptive information about the experiences and characteristics of a nationally representative sample of 10th-graders who were studied in the spring term of the 2001-02 school year. It examines the cohort's sociodemographic characteristics, school experiences, participation in extracurricular activities, time use, tested achievement in reading and mathematics, and educational expectations and plans.