William R. Miller, PhD, is Emeritus Distinguished Professor of Psychology and Psychiatry at the University of New Mexico. He introduced motivational interviewing in a 1983 article in the journal Behavioral Psychotherapy and in the first edition of Motivational Interviewing: Helping People Change, written with Stephen Rollnick, in 1991. Dr. Miller's research has focused particularly on the treatment and prevention of addictions, with broader implications for the psychology of change. He is a recipient of the international Jellinek Memorial Award, two career achievement awards from the American Psychological Association, and an Innovators in Combating Substance Abuse Award from the Robert Wood Johnson Foundation, among many other honors. The Institute for Scientific Information lists Dr. Miller as one of the world's most cited scientists.

Stephen Rollnick, PhD, is Honorary Distinguished Professor in the School of Medicine, Cardiff University, Wales, United Kingdom. He is a codeveloper of motivational interviewing, with a career in clinical psychology and academia that focused on how to improve conversations about change. He has worked in diverse fields, with special interests in mental health and long-term health conditions like diabetes, heart disease, and HIV/AIDS. Dr. Rollnick has published widely in scientific journals and has written many books on helping people to change behavior. He is coauthor (with William R. Miller) of the classic work Motivational Interviewing: Helping People Change, now in its third edition. He has traveled worldwide to train practitioners in many settings and cultures, and now works as a trainer and consultant in healthcare and sports.