In the past few years, the field of psychology has seen a dramatic increase in interest in the prevention of mental disorder and emotional difficulties. This special series provides some excellent examples of the promises held by a variety of prevention programs. At the same time, the papers in this volume highlight several important issues to consider and barriers to the implementation of prevention programs. This discussion paper explores the themes and issues raised by these papers and considers some of the lessons to be extracted for research into and implementation of prevention programs across mental health.