In the United States, routine smallpox vaccination ended in 1972. The level of immunity remaining in the U.S. population is uncertain, but is generally assumed to be quite low. Smallpox is a deadly and infectious pathogen with a fatality rate of 30 percent. If smallpox were successfully deployed as an agent of bioterrorism today, the public health and economic consequences could be devastating. Toward a Containment Strategy for Smallpox Bioterror describes the scientific results and policy implications of a simulation of a smallpox epidemic in a two-town county. The model was developed by an interdisicplinary team from the Johns Hopkins Bloomberg School of Public Health and the Brookings Institution Center on Social and Economic Dynamics, employing agent-based and other advanced computational techniques. Such models are playing a critical role in the crafting of a national strategy for the containment of smallpox by providing public health policymakers with a variety of novel and feasible approaches to vaccination and isolation under different circumstances. The extension of these techniques to the containment of emerging pathogens, such as SARS, is discussed. About the Authors Joshua M. Epstein and Shubha Chakravarty are with the Brookings Institution. Derek A. T. Cummings, Ramesh M. Singha, and Donald S. Burke are with the Johns Hopkins Bloomberg School of Public Health.