Keith Humphreys is a Professor and the Section Director for Mental Health Policy in the Department of Psychiatry and Behavioral Sciences at Stanford University. He is also a Senior Research Career Scientist at the VA Health Services Research Center in Palo Alto. His research addresses the prevention and treatment of addictive disorders, and, public policy information. In his talk he talks about how public policy is necessary to manage human interaction with potent psychoactive substances and their potential for great benefit and great harm.