The anthrax envelopes incident in the United States in 2001 created the impetus for a substantial increase in preparedness for bioterrorist threats among both public health and law enforcement professionals, worldwide. Ever increasing resources are now being allocated for dealing with a wide variety of potential threats, from the reintroduction of eradicated viruses such as smallpox to the possibility of genetically engineered novel pathogens. Despite the potentially devastating consequences of the various projected bioterror scenarios, it remains remarkably difficult to quantitatively assess the actual risk in each of these scenarios. Nevertheless, such risk assessment is crucial for determining the appropriate allocation of resources for research and preparedness. The public anxiety expected during a large-scale bioterrorism attack may even be more damaging than the direct effects of the bioterrorism agent, both in health-related and economic outcomes. Carefully tailored risk communication is a major tool for individuals, decision-makers or even entire communities to make educated decisions about their responses to well-being, and avoid social disruption. In this book, we have included articles from leading experts in the various disciplines associated with risk assessment and risk communication associated with bioterrorism. These papers are based on presentations at a NATO Advanced Research Workshop in Israel in June 2005, which addressed these issues. The resulting volume integrates the viewpoints of public health, law enforcement, risk analysis and media experts into a comprehensive, practical guide for approaching risk assessment and risk communication in a bioterrorism event.