am delighted to have been invited by three of my esteemed colleagues—the editors of this book—to write a foreword. The book represents a comprehensive and timely review of the multidisciplinary field of alcohol, drugs, and traffic safety—science, research, public policy, and litigation. The editors have assembled an outstanding roster of contributors, representing an international “who’s who” of academics, researchers, and thought leaders in the field. The various chapters give a broad perspective of the past, present, and future of the science of alcohol, drugs, and impaired driving. The field has reached a level of maturity, reflected by the many international efforts towards science-based laws and countermeasures, including widespread adoption of zero-tolerance and concentration per se laws for both illicit and selected licit psychoactive drugs in a driver’s blood; use of emerging technologies, such as roadside analysis of drugs in oral fluid; and collection of more reliable information about the negative influence of drugs on human performance and traffic safety. New problems requiring scientific solutions will, however, always emerge, as exemplified by the current trend in the United States and elsewhere towards legalization of marijuana use and the negative impact this might have on public health and traffic safety.