William R. Miller, PhD, is Distinguished Professor of Psychology and Psychiatry at the University of New Mexico, where he is also Codirector of the Center on Alcoholism, Substance Abuse, and Addictions. Dr. Miller's publications encompass more than 300 articles and chapters as well as 27 books, including [i]Quantum Change: When Epiphanies and Sudden Insights Transform Ordinary Lives[/i](with Janet C'de Baca). He maintains an active interest in pastoral counseling and the integration of spirituality and psychology. Dr. Miller is supported by a 15-year senior career Research Scientist Award from the National Institute on Alcohol Abuse and Alcoholism, which allows him to focus full time on clinical research.

Stephen Rollnick, PhD, is on the faculty in the Department of General Practice at the University of Wales College of Medicine. He has also worked for many years as a clinical psychologist in the British National Health Service. With a background in the addiction field, his interest turned to consultations about behavior change in wider healthcare practice, where practitioners try to encourage patients to change their lifestyle and use of medication. Dr. Rollnick's research and teaching activity is now focused on the behavior of practitioners and other topics. He has trained practitioners in many countries and continents, and has published a wide range of research papers, articles, and books.