This introduction presents the theme of this volume, the rationale for it, and the history of the conference series from which it originated. It provides also a short description of the papers included.

We consider a game-theoretic model of counterproliferation, in which a single Incumbent (holding nuclear weapons) is faced with a sequence of potential Entrants (who are considering developing and deploying a nuclear capability or other weapons of mass destruction of their own). The Incumbent...