J. Mark G. Williams, DPhil, is Professor of Clinical Psychology at the University of Wales, Bangor, where he has also served since 1997 as Director of the University's Institute of Medical and Social Care Research. Widely published, he is a founding fellow of the Academy of Cognitive Therapy.
John D. Teasdale, PhD, holds a Special Scientific Appointment at the Medical Research Council's Cognition and Brain Sciences Unit in Cambridge, England. He is a fellow of the British Academy, a fellow of the Academy of Medical Sciences, a founding fellow of the Academy of Cognitive Therapy, and a recipient of the American Psychological Association's Distinguished Scientist Award (Division 12).