This volume focuses on the question of how subject teaching can and must change to meet current challenges for the education system, which include the increasing diversity of individual learning backgrounds and inclusion. Using English, French, Spanish, mathematics, art, and music as examples, the conception and implementation of adequate teaching-learning arrangements based on the methodological approach of design-based research is explained. Furthermore, it is shown how professionalization in dealing with these and comparable processes of change can be effectively integrated into teacher training and school development processes.