1. Introduction With the demise the of the Cold War and in the aftermath of 9‧11, American leaders began voicing more concerns about unsecured nuclear material falling into the hands of Al Qaeda and other terrorist networks. The concern is not generally over nuclear warheads in the possession of declared nuclear states, although political instability in Pakistan continues to raise concerns over its ability to maintain and secure its nuclear weapons.1 The main concerns arise from securing nuclear materials in the possession of countries which are either actively in pursuit of nuclear weapons program, such as North Korea, Iran, and Syria or countries which have a questionable capacity to safeguard the nuclear material already in their possession. These two types of countries make it more likely that terrorist networks may eventually succeed in acquiring both the technology and the material to create a nuclear device.

Preface Ⅰ. Nuclear Summit 2012 and U.S.-ROK Strategic Cooperation/ Jae H. Ku, Jung-Ho Bae Ⅱ. The Evolution of U.S. Nuclear Strategy: From Massive Retaliation to the Nuclear Posture Review/ Thomas M. Nichols Ⅲ. The Current Status of the Non-Proliferation Regime/ Yong shik Choo Ⅳ. Combating North Korea´s Nuclear Blackmail: Proactive Deterrence and the Triad System/ Taewoo Kim Ⅴ. Three States, Three Stories: Comparing Iran, Syria and North Korea´s Nuclear Programs/ Jim Walsh Ⅵ. South Asia and the Strategic Implications of Nuclear Weapons/ Walter Andersen Ⅶ. Nuclear Weapons and Non-State Actors: Issues for Concern/ Sharon K. Weiner Ⅷ. New Nuclear Renaissance: Challenges for Nuclear Non-Proliferation?/ Jae Jeok Park Ⅸ. China´s Way to Go Nuclear/ Teng Jianqun Ⅹ. ROK-U.S. Strategic Cooperation/ Young-Ho Park