This report examines the state of public and private school library media centers in the United States in 1999-2000. The data used in the report come from the 1999-2000 Schools and Staffing Survey (SASS), the nation's most extensive sample survey of America's public and private schools and library media centers. Sponsored by the National Center for Education Statistics (NCES), SASS has been conducted four times, in school years 1987-88, 1990-91, 1993-94, and 1999-2000. Currently, the library media center is defined as an organized collection of printed and/or audiovisual and/or computer resources that is administered as a unit, is located in a designated place or places, and makes resources and services available to students, teachers, and administrators. Appended are: (1) Standard Error Tables; (2) Technical Notes; (3) Supplemental Tables; and (4) Glossary. (Contains 39 tables.)