An new article by Zia Mian in The Bulletin of the Atomic Scientists, looks at the challenges facing the transition to a nuclear-free world. These include the nature of the disarmament process, the issue of reversibility, the management and elimination of stockpiles of fissile materials, and the risks of nuclear weapon reconstruction and proliferation using materials and capabilities in civilian nuclear energy programs. Read the full article. Mian is a physicist and directs the Project for Peace and Security in South Asia at Princeton University's Program on Science and Global Security.