How do we understand the nuclear strategies of regional powers and how successful are those strategies in deterring conflict? These are obviously important questions for students of world politics, but unfortunately they are also questions that have been largely ignored as scholars focused their attention on the nuclear superpowers of the bipolar era. Of course, the relative lack of attention paid to regional nuclear powers would not matter all that much if these states acted similarly to the superpowers, but it is clear that they have acted quite differently. For example, none of the regional nuclear powers has attempted to build the large arsenals possessed by the superpowers during the Cold War. In his important and ambitious new book, Vipin Narang attempts to explain the decisions made by regional nuclear powers and to develop a new theoretical framework that will be relevant to understanding the current and future dynamics of what he calls the “second nuclear age”(1).