Motivational interviewing is a client-centered, directive method for facilitating change by helping people to explore and work through ambivalence. It was introduced by Dr. William R. Miller in 1983, and has been developed in collaboration with Dr. Stephen Rollnick.
Key readings are:
Miller, W. R. (1983). Motivational interviewing with problem drinkers. Behavioural Psychotherapy, 11, 147-172. (The original description of this method)
Miller, W. R., & Rollnick, S. (2002). Motivational interviewing: Preparing people for change (2nd ed.). New York: Guilford Press.
In addition to the information available on this site, there is extensive information, including a comprehensive bibliography, at www.motivationalinterviewing.org