The problem of the relation of theory to practice in teaching and teacher training has been a major issue of debate for a long time. Well over a century ago, Dewey (1904) discussed the tensions between the role of theoretical insight as a preparation for the teaching profession versus the need for more practical, how-to-do-it courses in which one learns to manage the classroom situation in productive manners. Dewey's position was to argue for the vital role of research-based, academic knowledge in psychology, philosophy of education and the subject to be taught in developing educational practices. Discussions of this kind have since been carried on more or less intensively in many contexts analysing teacher training and professional development. New research traditions, allegedly bridging the gap, have emerged. For instance the extensive research on teacher thinking. Before discussing what video technology and videopapers can contribute to overcoming this gap between teaching and research on teaching and learning, the author first considers the implications of conceiving these problems as between "theory" and "practice". Then, the author discusses the role of video documentation and videopapers in teacher education and in-service training (as well as in other professions).