This book analyzes the United States and Russia’s nuclear arms control and deterrence relationships and how these countries must lead current and prospective efforts to support future nuclear arms control and nonproliferation.  The second nuclear age, following the end of the Cold War and the demise of the Soviet Union, poses new challenges with respect to nuclear-strategic stability, deterrence and nonproliferation.  The spread of nuclear weapons in Asia, and the potential for new nuclear weapons states in the Middle East, create new possible axes of conflict potentially stressful to the existing world order.  Other uncertainties include the interest of major powers in developing a wider spectrum of nuclear weapons and delivery systems, possibly for use in limited nuclear wars, and the competitive technologies for antimissile defenses being developed and deployed by the United States and Russia.  Other technology challenges, including the implications of cyberwar for nuclear deterrence and crisis management, are also considered.  Political changes also matter.  The early post-Cold War hopes for the emergence of a global pacific security community, excluding the possibility of major war, have been dashed by political conflict between Russia and NATO, by the roiled nature of American domestic politics with respect to international security, and by a more assertive and militarily competent China. Additionally, the study includes suggestions for both analysis and policy in order to prevent the renewed U.S.-Russian nuclear arms race and competition in new technologies. This volume would be ideal for graduate students, researchers, scholars and anyone who is interested in nuclear policy, international studies, and Russian politics.