This chapter presents some closing thoughts on key concepts discussed in the preceding chapters of this book. The hierarchical equilibrium theory has been formulated and tested and found to be associated with the absence of systemic war. Multipolarity has been tied analytically to this sort of inequality, with bipolarity as a much less likely candidate for that dubious distinction. A normative justification for the expectation of peace upon the existence of such equilibrium, especially its aspects of equality and positive-sum games, has been developed. In a larger sense, an effort to pursue the development of empirically valid theory that is not solely rooted in the traditional power politics paradigm and may be seen to have a certain kinship with neorealist theory. Theoretically, in addition to the basics of the hierarchical equilibrium theory and the finding of the analytic instability of multipolar systems, there exists another, somewhat unexpected theoretical implication.