This work seeks to develop a new concept with which to analyse the actions and activities of states that tend to be relatively ignored by the discipline of International Relations (IR). As a discipline, IR has a tendency to lean towards the analytically safe. Given the current and recent dynamism of the international system that is both surprising and undesirable. Arranged around the concept of the idea of the Cusp state (and cuspness more generally), the book consists of empirical analysis of eight different countries Brazil; Iran; Israel; Japan; Mexico; Taiwan, Turkey; Ukraine, defined as...