This book is an analysis of why some – but only some – political leaders decide to endow their states with nuclear weapons. It finds that decisions to go or not to go nuclear result not from the international structure, but rather from individual hearts. Simply put, some political leaders hold a conception of their nation's identity that leads them to desire the bomb; and such leaders can be expected to turn that desire into state policy.

The book's focus on individual leaders is unusual in the social-scientific literature on proliferation and non-proliferation. Indeed, most authors on the subject hardly even bother to ask the question of how leaders come to desire nuclear weapons. Instead, they simply adopt a tragic sensibility, viewing nuclear weapons as a symptom of a fallen humanity's raw quest for power. More than a few even explicitly and unironically refer to nuclear weapons as “temptations,” to those who succumb to those temptations as “nuclear sinners,” and to the goal of non-proliferation efforts as the construction of an inevitably fragile “nuclear taboo.” This book takes a different tack. It starts its analysis by pointing out the basic fact of the history of nuclear proliferation: the large and fast-growing number of nuclear-weapons capable states, contrasted with the small and slow-growing number of actual nuclear weapons states. This combination of widespread capability with widespread restraint, which has persisted despite numerous shocks, is baffling until one sheds the tragic sensibility.