Stephen Rollnick, PhD, is Honorary Distinguished Professor at the Cochrane Institute of Primary Care and Public Health at Cardiff University, United Kingdom. A clinical psychologist with many years of experience and a codeveloper of MI, as well as a cofounder of the Motivational Interviewing Network of Trainers, Dr. Rollnick provides consultancy and training on the subjects of motivation, change, and MI. His research and guidelines for good practice have been widely published, and his work on implementation continues, with a current focus on children with HIV/AIDS in Africa, pregnant teens in deprived communities, and MI for teachers and sports coaches. With William R. Miller, Dr. Rollnick is coauthor of the classic work Motivational Interviewing: Helping People Change, now in its third edition.

William R. Miller, PhD, is Emeritus Distinguished Professor of Psychology and Psychiatry at the University of New Mexico, where he joined the faculty in 1976. He served as Director of Clinical Training for UNM's American Psychological Association-approved doctoral program in clinical psychology and as Codirector of UNM’s Center on Alcoholism, Substance Abuse, and Addictions. Dr. Miller’s publications include 35 books and more than 400 articles and chapters. He introduced the concept of motivational interviewing in a 1983 article. The Institute for Scientific Information names him as one of the world's most cited scientists.

Christopher C. Butler, MD, is Professor of Primary Care Medicine and head of the Department of Primary Care and Public Health at Cardiff University, UK. He trained in medicine at the University of Cape Town and in clinical epidemiology at the University of Toronto. For his doctoral work, under the direction of Stephen Rollnick, he developed and evaluated behavior change counseling and conducted qualitative research into patients’ perceptions of advice against smoking from clinicians. Dr. Butler has published more than 70 papers, mainly on health behavior change and common infections. He has a general medical practice in a former coal-mining town in south Wales.