This study examines the factors that will shape states' nuclear weapons policies this century. It discusses and evaluates the influence of key strategic relationships, military threats and technological developments, domestic factors, changing concepts of security, and the evolution of arms management and limitation regimes. It analyzes various types of disarmament and arms control strategies and the verification techniques and frameworks that might sustain them. Against this background, the paper identifies four possible nuclear futures, and assesses the capabilities and limitations of the tools which might prevent the emergence of a high-salience nuclear future. In association with Mountbatten Centre for International Studies, University of Southampton.