In the last decades, progress in the field of pre-service and in-service teacher education has been evident. Despite the developments of curriculum programs, models and designs, various challenges are shaping the field. Models of teacher education are usually presented as “research-based”, but related research is often invisible or fragmented. The “support for teachers” and the “improvement of instruction” are only loosely coupled and their interdependence is not highlighted. These challenges were the impetus to initiate this publication. Individual approaches, models or designs of pre-service and in-service teacher education developed by the authors (action research, video clubs, lesson studies, and others) are introduced and their impact and shortcomings for further development are specified. In the concluding chapter, a reflective discussion across individual approaches to reveal particular issues that are shaping the field is provided. Practitioners as well as researchers in the field of teacher education can benefit from this book.