In this book, a former White House National Security Advisor, a former Chairman of the Joint Chiefs of Staff, and a leading scientist, offer a thoughtful prescription for effective international action to cut existing nuclear arsenals and prevent their further proliferation. They argue that the immediate tasks are to execute the already agreed-upon bilateral reductions in US and Russian forces, ensure that Russia remains the only nuclear state of the old Soviet Union, and substantially strengthen the international effort against the spread of nuclear weapons through tougher monitoring. The authors favour adoption of a strict doctrine of using nuclear weapons only as a "defensive last resort," along with other specific changes in current policy. Prominent in their prescriptions is an eventual drastic reduction of the currently agreed Russian-American warhead ceiling.