The proliferation of nuclear weapons is a serious threat to international security and peace. Particularly, the cases of Iran and North Korea, and the recent processes including the Seoul Nuclear Security Summit are illustrating the importance of nuclear non-proliferation regime in international affairs. This regime, for more than forty years, aims to provide services for the prevention of proliferation and use of nuclear weapons. The IAEA, CTBTO, the NPT Review Conferences and other internationally important institutions of this area are trying to be providers of the nuclear weapon-free world and barometers of the health of the non-proliferation regime. The aim of this book is to assess the effectiveness of the Nuclear Non-Proliferation Regime. An analyzing of the regime in the book is guided by the regime theory, international law and politics, identifying and interpreting applicable rules and norms that are establish the nuclear non-proliferation regime, and assessing how well enforcement of the regime is carried out and what are the future reforms might be.