Within the next decade, many thousands of U.S. and Russian nuclear weapons are slated to be retired as a result of nuclear arms reduction treaties and unilateral pledges. A hundred tons or more of plutonium and tons of highly enriched uranium will no longer be needed. The management and disposition of these fissile materials, the essential ingredients of nuclear weapons, pose urgent challenges for international security. This book offers recommendations for all phases of the problem, from dismantlement of excess warheads, through intermediate storage of the fissle materials they contain, to ultimate disposition of the plutonium.