NATO's leaders never tire of calling the organization the most successful military alliance in history.It has gone from defending its members against a Soviet attack to engaging in humanitarian intervention in the Balkans to patrolling the Mediterranean Sea. At its recent sixtieth anniversary, however, the celebration was tempered by charges that the alliance was failing in Afghanistan. Today, the central question facing NATO is whether an alliance designed to confront traditional twentieth-century threats can respond to the transnational challenges of the twenty-first century. The Future of NATO argues that NATO members must recognize two features of the new security environment.First, threats are global, not local, and often are nonmilitary in nature; and second, NATO cannot manage many of these new threats on its own and must seek other partners, such as the European Union, to be effective. In addition, James M. Goldgeier maintains the alliance must come to a consensus on how to manage its relationship with an increasingly assertive Russia.