Americans in the twenty-first century are keenly aware of the many forms of terrorism: hijackings, biological attacks, chemical weapons. But, the deadliest form is almost too scary to think about - a terrorist group exploding a nuclear device in an American city. In the urgent call to action, Graham Allison, one of America's leading experts on nuclear weapons and national security, presents the evidence for two provocative, compelling conclusions. First, if policy makers in Washington keep doing what they are currently doing about the threat, a nuclear terrorist attack on America is inevitable. Second, the surprising and largely unrecognized good news is that nuclear terrorism is, in fact, preventable. Allison offers an ambitious but feasible blueprint for eliminating the possibility of nuclear terrorist attacks, if we are willing to face the issue squarely.