This book contains an up-to-date analysis on the legal aspects of nuclear non-proliferation and disarmament. It scrutinises the effectiveness, the limits, the adaptation, and the future challenges of the regime on the control of nuclear weapons which is still based on the 1968 Treaty on the Non-Proliferation of Nuclear Weapons (NPT) and guaranteed by the IAEA controls. It also deals with new challenges to the non-proliferation legal order deriving mainly from new weapon states, the North Korean withdrawal from the NPT, the Iranian nuclear programs, activities from non-state actors, the easier access of states and other entities to sensitive materials, the still remote entry into force of the Comprehensive Test Ban Treaty and the debate on a fissile material cut-off treaty. As nuclear proliferation and disarmament remain among the few issues that can threaten international peace and security, this up to date analysis cannot fail to be of interest to academics and practitioners in this field.