Concern over school staffing problems has given impetus to empirical research on teacher shortages and turnover. As a result, the National Center for Education Statistics (NCES), the statistical arm of the U.S. Department of Education, designed the Schools and Staffing Survey (SASS) and its supplement, the Teacher Follow-up Survey (TFS), in the late 1980s. Over the past decade and a half, the author has been undertaking research using SASS and TFS to study a number of issues concerned with teacher supply, demand, and quality. In this chapter, he briefly summarizes what the data tell us about the realities of school staffing problems and teacher shortages, especially for mathematics and science teachers.