This report presents national data on the extent to which students in the nation’s public secondary schools are taught by teachers without basic qualifications in their assigned teaching fields. It seeks to address the question of whether inequalities exist in the distribution of adequately qualified teachers across and within different schools in the United States. The report is based on data from the 1990-91 Schools and Staffing Survey, a nationally representative survey conducted by the National Center for Education Statistics. The premise underlying this analysis is that adequately qualified staffing requires teachers at the secondary school level to hold, as a minimum prerequisite, at least a college minor in the fields they teach. Knowledge of subject matter does not, of course, guarantee qualified teachers, nor quality teaching. The premise is that basic subject knowledge is a necessary prerequisite for both.