For thousands of years, Realpolitik has been the pre-eminent lens through which scholars and practitioners alike have examined international politics. Nevertheless, it remains controversial, generating quarrels at both the theoretical and the empirical levels. Positing that the vagueness of the key concepts of Realpolitik causes much of the disagreement, Cusack and Stoll argue that a computer simulation embodying those concepts can be a valuable tool for investigating, and illustrating, the theoretical properties of multi-state systems. They use their own simulation to conduct experiments concerning the paramount questions of Realpolitik - why do individual states behave as they do? What strategies enhance or minimize their success in international politics? What accounts for the basic character and dynamic of the interstate system?