Fran H. Norris, PhD, a community/social psychologist, is a Research Professor in the Department of Psychiatry at Dartmouth Medical School, where she is affiliated with the National Center for PTSD and with the National Consortium for the Study of Terrorism and Response to Terrorism, headed by the University of Maryland. She has published extensively on the psychosocial consequences of disasters. nbsp; Sandro Galea, MD, DrPH, is an Associate Professor of Epidemiology at the University of Michigan School of Public Health and a Research Affiliate of the Population Studies Center at the Institute for Social Research. His research focuses on the social and economic production of health, particularly mental health and behavior in urban settings, and he has an abiding interest in the social and health consequences of collectively experienced traumatic events. nbsp; Matthew J. Friedman, MD, PhD, is Executive Director of the National Center for PTSD and Professor of Psychiatry and Pharmacology at Dartmouth Medical School. He has worked with patients with PTSD for more than 30 years and has written or edited 180 books, monographs, chapters and peer-reviewed journal articles. nbsp; Patricia J. Watson, PhD, is an educational specialist for the National Center for PTSD and Assistant Professor in the Department of Psychiatry at Dartmouth Medical School. She collaborates with the Substance Abuse and Mental Health Services Administration, the Centers for Disease Control and Prevention, and subject-matter experts to create publications for public and mental health interventions following large-scale terrorism, disaster, and pandemic flu.