Hal Arkowitz, PhD, is Associate Professor of Psychology at the University of Arizona. His main interests are in understanding how people change and why they don’t. Dr. Arkowitz has published widely in the areas of anxiety, depression, psychotherapy, and psychotherapy integration. Along with Scott O. Lilienfeld, he is a co-columnist for the magazineScientific American Mind. A past Editor of theJournal of Psychotherapy Integration, he maintains an active clinical practice. nbsp; Henny A. Westra, PhD, is Associate Professor in the Department of Psychology and the Director of the Anxiety Research Clinic at York University in Toronto. Prior to this, she was the Clinical Director of the Anxiety and Affective Disorders Service at the London Health Sciences Centre. Dr. Westra has published over 30 peer-reviewed articles and book chapters, as well as given over 100 presentations and workshops, on the treatment of anxiety. She has received funding from the National Institute of Mental Health and the Canadian Institutes of Health Research for her research on motivational interviewing, expectations for change, and engagement with treatment. nbsp; William R. Miller, PhD, is Emeritus Distinguished Professor of Psychology and Psychiatry at the University of New Mexico. With over 400 publications, including 35 books, Dr. Miller introduced the concept of motivational interviewing in a 1983 article. He was named by the Institute for Scientific Information as one of the world's most cited scientists. nbsp; Stephen Rollnick, PhD, is a clinical psychologist and Professor of Health Care Communication in the Department of Primary Care and Public Health, Cardiff University, Wales, United Kingdom. He has published widely on motivational interviewing and health behavior change and has a special interest in challenging consultations in health and social care.