William F. Cornell, M.A., is a teaching and supervising transactional analyst and psychotherapist with more than 40 years of clinical, supervisory and training experience. Based in the United States, he has worked as a clinician, consultant and educator, with a particular focus on ethics, professional development and contemporary theory in transactional analysis. He has served as co-editor of the Transactional Analysis Journal and as editor of the Innovations in Transactional Analysis book series, and is widely recognized for his scholarly and professional contributions to the international transactional analysis community.