How do students become professionally acting teachers, and what significance do practical studies have for stimulating and supporting their professionalization process? Although practical phases in teacher education have always been considered highly important, they have been relatively overlooked in educational research for many years. Recently, a scientific discourse has emerged that is characterized by increasingly diverse methodological and methodological approaches. This is also reflected in the contributions of this volume. The empirical studies presented here provide insights into processes of professional development in the first and second phases of training, as well as the impact of individual prerequisites and contextual conditions.