The National Defense University recently hosted a major symposium to address the challenges to U.S. national security and international stability posed by the spread of weapons of mass destruction: nuclear, chemical, and biological weapons, and missiles as a means of delivery. The need to examine such issues is clear. Perhaps no problem facing civilian and military decision makers today is as urgent and important as the effort to control the proliferation of such weapons. Put simply, WMD proliferation represents one of the most complex and fundamental threats to security today. Attended by many of the premier experts in the field, the NDU Symposium explored a broad spectrum of issues ranging from the incentives and disincentives for proliferation to non- and counterproliferation policies and programs. The panelists discussed such critical issues as how effectively present controls to prevent proliferation are working and how to protect against proliferation when it occurs. Most impressively, the participants ventured to identify alternative perspectives and approaches that may contribute to meeting the common challenges. All this unfolds in the pages that follow. It is a search for wisdom, for, as Cicero said twenty centuries ago, Weapons are of little use on the field of battle if there is no wise counsel at home. Ervin J. Rokke Lieutenant General, USAF President, National Defense University