Spurred on by regulations outlined in the No Child Left Behind Education Act of 2001 (NCLB), educators and policy makers are gearing up to solve the problem of producing enough highly qualified teachers to meet the country's rapidly growing demand. According to the U.S. Department of Education, rising enrollments and increasing teacher retirements will create a need to produce more than 2 million new public and over a half-million independent school teachers over the next ten years. The quantitative need comes from demand for new teachers to replace those who are retiring or otherwise leaving, to teach a growing population of students, to teach more students with special needs, and so forth. The problem of providing a sufficient number of qualified teachers, however, is not the result of the NCLB legislation alone. Although a common explanation is that two demographic trends are interacting to create a shortage, increasing enrollments and teacher retirement may not be the whole picture. One researcher reports that the annual turnover rate for teachers is significantly higher than the average annual turnover rate across all occupations, and concludes that a key issue is one of retaining teachers who are already in classrooms. Another factor in understanding the teacher shortage has to do with the distribution of teachers. While some school systems have an excess of applicants for teaching positions, others struggle to fill open spots. Finding ways to distribute new teachers to the areas that need them the most is a major challenge for policy makers and school administrators. The need to prepare and retain qualified teachers is related to several other education issues: policies that reduce class size typically result in the need for more teachers; changes in demographics create the need for more English as a Second Language teachers; and an increasing number of identified special needs students contribute to the widespread scarcity of special education teachers. Other factors related to the teacher shortage include inconsistencies in licensing requirements across states and the slowness of state and school bureaucracies to deal with credentialing and licensure issues. Although colleges have been producing a steadily increasing number of graduates who are prepared to be teachers, even with steady or slightly increasing production of new teachers, the supply of teachers cannot keep up with increasing demand. In order to meet the projected need for new teachers over the next ten years, most educators and policy makers agree we must not only increase the supply of new teachers, we must reduce the large number of existing teachers who leave the profession for reasons other than retirement. The problem facing the country now is akin to building a bike while riding it: the country must produce and distribute millions of highly qualified teachers while it simultaneously reinvents the ways it prepares them, revamps the conditions in which they work, and restructures the economics underlying school funding. (Contains 34 endnotes.) [This brief was produced by the Center for Child and Family Policy, Duke University, Terry Sanford Institute of Public Policy.]