The period covered by these six figures marks many transformational changes, among the most important of which is, according to Kissinger, the shift “from a hereditary and aristocratic model of leadership to a middle-class and meritocratic one” (394). In previous centuries, aristocracy was a hereditary system of rulers who had more in common with their counterparts in other nations than members of the lower classes within their own countries. These social networks were meant to limit conflict, which it largely did until World War I. In the wake of that war there was an outburst of populist ideologies, including liberalism and nationalism, which promised to tap the talents of ordinary citizens. Kissinger states that the six leaders profiled are all accordingly figures from middle- or lower-class backgrounds who had to rise through the ranks in one form or another to reach the pinnacle of political power, relying on education, opportune timing, and a bottomless well of confidence in their own abilities to do so. Because they were to some extent outsiders, Kissinger states that “they were often tellers of hard truths” (401). They questioned prevailing modes of orders, articulated daring alternatives, and were not afraid of the divisions such choices would invariably cause.