"Purdon and Clark are among the world's top experts on the nature and treatment of unwanted obsessional thoughts. In this book, they describe powerful methods for conquering this problem, based on their own research as well as studies by other leading scientists. Although most self-help books on OCD include sections on dealing with unwanted thoughts, this excellent book provides the most thorough discussion of this topic that I've seen. Whether you have disturbing religious thoughts that you can't get rid of, irrational, unwanted, aggressive or sexual impulses, or other sorts of upsetting thoughts, this book is for you!" --Martin M. Antony, Ph.D., ABPP, director of the Anxiety Treatment and Research Centre at St. Joseph's Healthcare and professor in the Department of Psychiatry and Behavioural Neurosciences at McMaster University, both in Hamilton, Ontario

David A. Clark, PhD, L. Psych., is professor of psychology at the University of New Brunswick in Fredericton, NB. He has published numerous articles on cognitive theory and therapy of depression and obsessive-compulsive disorder and is a founding fellow of the Academy of Cognitive Therapy. He is coauthor of Scientific Foundations of Cognitive Theory and Therapy of Depression with Aaron Beck and Brad Alford, and he has recently published the Clark-Beck Obsessive Compulsive Inventory with the Psychological Corporation. He has received a number of research grants to study the cognitive basis of distress. He is also an active member of the Obsessive-Compulsive Cognitions Working Group and is associate editor of Cognitive Therapy and Research.

Christine Purdon, PhD, C. Psych., is associate professor of psychology at the University of Waterloo in Waterloo, ON, and is also a consulting psychologist with the Anxiety Treatment and Research Centre at St. Joseph's Healthcare in Hamilton, ON. She is a licensed psychologist who has been researching and treating obsessional problems for the past decade. She received three early career awards for her contributions to research on obsessive-compulsive disorder (OCD) and is a member of the Obsessive-Compulsive Cognitions Working Group, an international research group devoted to examining the role of cognitive appraisal in the development and persistence of OCD. She is a member of the Academy of Cognitive Therapy and divides her time between conducting research on OCD; assessing and treating OCD and other anxiety problems; and training residents, PhD students, and students in other mental health professions in cognitive-behavioural therapy and treatment of anxiety disorders. She is currently coauthoring a comprehensive book on treatment of OCD for professionals under contract with the American Psychological Association Press.