Jonathan P. Caulkins is Stever Professor of Operations Research and Public Policy at Carnegie Mellon University. Angela Hawken is associate professor of public policy at Pepperdine University. Beau Kilmer is co-director of the RAND Drug Policy Research Center. Mark Kleiman is professor of public policy at UCLA. They are the authors of Marijuana Legalization: What Everyone Needs to Know (Oxford University Press, 2012).