This report presents first findings from the Base Year of the Education Longitudinal Study of 2002 (ELS:2002). ELS:2002 is the fourth major secondary school longitudinal study sponsored by NCES, closely reflecting the research purposes and designs of its three predecessor studies NLS-72, HS&B, and NELS:88. Beginning with a nationally representative sample of 10th-graders in 2002, ELS:2002 is designed to provide data about critical transitions experienced by students as they proceed through high school and into postsecondary education or the workplace. This E.D. Tabs report summarizes the sociodemographic and educational characteristics of the sophomore class of 2002. These characteristics are captured in a series of student- and school-level classification variables. At the student level, these variables are: sex, age, race/ethnicity, language minority status, family composition, parental education, student's expectations, and tested achievement. Also included are three characteristics of each student's school: sector (public, Catholic, or other private), metropolitan status (urban, suburban, or rural), and region in which schools are located (Northeast, Midwest, South or West). Appended are: (1) Technical Notes and Glossary; and (2) Technical Notes and Glossary. (Contains 6 tables & 6 figures.)