Stephen M. Meyer steps back from the emotions and rhetoric surrounding the nuclear arms debates to provide a systematic examination of the underlying determinants of nuclear weapons proliferation. Looking at current theories of nuclear proliferation, he asks: Must a nation that acquires the technical capability to manufacture nuclear weapons eventually do so? In an analysis, remarkable for its rigor and accessibility, Meyer provides the first empirical, statistical model explaining why particular countries became nuclear powers when they did. His findings clearly contradict the notion that the pace of nuclear proliferation is controlled by a technological imperative and show that political and military factors account for the past decisions of nations to acquire or forgo the development of nuclear weapons.