This chapter sets out the elements of Evolutionary Game Theory (EvGT hereafter). In particular, we focus on how EvGT may contribute the problem of Indeterminacy (i.e. of how an equilibrium is selected in the presence of multiple equilibria) and to debates in social science. One such debate concerns the role of the State and we have spent considerable time in the earlier chapters bringing out what game theory can contribute to this debate. In this chapter, we shift our attention to the discussion of power, history and functional explanation in social science.