In this occasional series, we record the views and personal experiences of people who have especially contributed to the evolution of ideas in the journal's field of interest. Dr Walter Ling is a neurologist and psychiatrist, and is Director of the Integrated Substance Abuse Programs (ISAP) at the University of California, Los Angeles (UCLA), one of the foremost substance abuse research groups in the world. Dr Ling led pivotal clinical trials in the United States for all three of the only US Food and Drug Administration-approved opiate pharmacotherapies, levo-acetylmethadol (LAAM), buprenorphine and naltrexone, and is leading ongoing efforts for approval for sustained-release buprenorphine.