José Goldemberg, University of São Paulo; Tatsujiro Suzuki, University of Tokyo; Frank von Hippel, Princeton University; William Walker, University of St Andrews. This session was part of the 2007 Carnegie International Nonproliferation Conference, “Tomorrow's Solutions,” June 25–26, in Washington, D.C., which addressed the critical challenges confronting the nonproliferation regime and offered policy recommendations to stop the spread and use of nuclear weapons and materials.