Motivational Interviewing (MI) is a promising 25-year-old therapeutic approach that integrates relationship-building principles and more directive strategies to move clients toward behavioral change. A large and expanding number of controlled research studies of MI have demonstrated its efficacy for addictive behaviors ranging from use of alcohol, nicotine, cocaine, heroin, and marijuana to gambling. This commentary highlights how the articles in this special series have answered two interrelated remaining questions about MI: first, whether it works beyond addictions; second, whether it adds significantly to the efficacy of cognitive behavioral therapy (CBT) when combined with it as either a pretreatment or throughout treatment. The articles in this series provide excellent rationales for why MI should work for problems such as eating disorders, depression, anxiety, and suicide, and why combining it with CBT should enhance client outcomes for each of these areas. However, there is a paucity of research data--especially from clinical trials--to support the theories, leaving practitioners with a conflict between the two intertwined poles of practice and science.