Despite the multiple changes that have happened in medical education over the last three decades, it is often speculated that these changes have been made in the absence of supportive theory, or at least by a poor understanding of educational theory. It is similarly expounded that the continuance of this change is not supported by either initial educational research or research into the effect of educational intervention. This commentary explains the background reasoning and intended structure of the new AMEE Guides in Medical Education Theories Series, in which it is intended to bring together the theories in education with both the practice and research activities, demonstrating the interactivity between the three and providing the reader...