Based on a major international teacher education research project—the Mathematics Teaching in the 21st Century Study (MT21)—this book investigates the preservice preparation of middle school mathematics teachers in the United States, South Korea, Taiwan, Germany, Bulgaria, and Mexico. The study was funded by the National Science Foundation and the participating countries. William Schmidt (co-author of the influential TIMSS study on student test results in science and math) and Maria Teresa Tatto (director of the Teacher Education and Development study, or TEDS-M) led a collaborative team of international researchers in this study. Using the results of more than 2,500 surveys, the authors examine the differential contribution of the six countries’ teacher-education models to the knowledge, skills, and dispositions of their future mathematics teachers. Case studies and detailed analyses of the teacher education curriculum across the participating countries provide rich contextual information to explain the survey findings. This study is the first to examine the resource allocation and economic support in teacher education vis-à-vis other mathematics-related professions, and it shows that differential investment patterns are consistent with the level of teaching knowledge found in each country’s new teachers. The book includes a chapter on policy implications, with a special focus on teacher preparation in the United States.