Since 2001, tremendous amounts of information have been gathered regarding terrorist cells and individuals potentially planning future attacks. There is now a pressing need to develop new mathematical techniques to assist in the analysis of this information, both to quantify future threats and to quantify the effectiveness of counterterrorism operations and strategies. Concepts and techniques from mathematics have already been applied to counterterrorism. The following is a partial list of such problems: strategies for disrupting terrorist cells; border penetration and security; terrorist cell formation and growth; data analysis of terrorist activity; terrorism deterrence strategies; and emergency response and planning. A primary intention of the symposium is to present talks by representatives from industry, academia, the national labs, and the military that are accessible to the broader public, especially policy-makers, politicians, and members of the intelligence and law enforcement communities.