In the global era, teachers must have the preparation and skills to teach students to the highest standards. U.S. efforts to improve teacher education have resulted in some excellent opportunities for educators to learn and refine their craft, but, as Ms. Darling-Hammond indicates, systemic reform has proved elusive. She suggests looking to our international counterparts for guidance. AROUND THE world, the importance of education to individual and societal success has increased at a breathtaking pace as a new knowledge-based economy has emerged. As a consequence, most countries have been engaged in intensive reforms of their education systems, and many have focused especially on improving teacher education, recognizing that preparing accomplished teachers who can effectively teach a wide array of learners to high standards is essential to economic and political survival. INNOVATION IN THE UNITED STATES In the U.S., a growing consensus about the importance of teachers has led to reforms of teacher education, the development of professional teaching standards, and the No Child Left Behind requirement that schools employ only highly qualified teachers. Among the resulting innovations are teacher education models that allow more extensive study of specific disciplines, along with more intensive clinical training in schools. Some new models are one-or two-year graduate programs that serve recent graduates or mid-career recruits. Others are five-year programs that begin during the undergraduate years. Because the graduate year in these models allows students to focus exclusively on the task of preparing to teach, such programs make possible yearlong school-based internships that are tightly integrated with coursework on teaching. (1) Many of these programs have joined with school districts to create professional development schools, which--like teaching hospitals in medicine--provide sites for state-of-the-art practice as well as for training novices, offering professional development to veteran teachers, and conducting research. And research has shown that many of these schools have improved teaching practice and student achievement, while building professional knowledge. (2) Many states have strengthened licensing standards in an effort to ensure that teachers are able to teach learners from different backgrounds and with various levels of preparation to meet challenging new content standards. And the standards and portfolio assessments of the National Board for Professional Teaching Standards have stimulated interest worldwide, as other countries are seeking to develop similar systems for supporting the in-depth study of teaching and for offering the recognition of excellence. At the same time, however, some political forces oppose the professionalization of teaching and argue for reducing the barriers to entry posed by standards for preparation. (3) As budget crises have caused many poor districts to lower standards in order to fill teacher vacancies, teachers' access to knowledge--and students' access to well-qualified teachers--has become more unequal than ever before. While a growing number of teachers are prepared in rigorous new programs, others enter the profession through alternatives that provide few courses and no student teaching. At least 50,000 individuals enter teaching each year without training, and most of them are assigned to teach the nation's most vulnerable students in the highest-need schools. (4) Finally, professional development in most districts still consists primarily of one-shot workshops, rather than more effective problem-based learning that is built into teachers' ongoing work with their colleagues. As a result, many U.S. teachers enter the profession with inadequate preparation and then have few opportunities to enhance their knowledge and skills over the course of their careers. LESSONS FROM OTHER COUNTRIES Whereas the decentralized U. …