Drawing together an international author team from Australia, Finland, France, Germany, Norway, Sweden and the UK, this book examines how we might democratize and open up access to 'knowledge of the powerful' for all. This book moves beyond the narrow knowledge vs skills debate of the 20th century to interrogate the epistemic quality of education in schools, and is a valuable resource for reflecting on the design and implementation of teacher education. Based on a range of national studies by the Knowledge and Quality across School Subjects and Teacher Education network (KOSS), funded by the Swedish Research Council (2019-22), the chapters explore teachers' powerful professional knowledge and the implications this has for innovation in teacher education, policy and practice in educational settings.