‘Middle class,’ ‘economy,’ ‘the family as the fundamental unit of the state,’ ‘politics,’ ‘constitution,’ ‘civic duty’—we use these words and expressions without even realizing that we owe their very existence to Aristotle. He was a brilliant thinker who first introduced them in his work *Politics*, where he also pioneered social and political philosophy, establishing the study of social relations as a distinct discipline for the first time in history. ‘Man is by nature a political animal,’ Aristotle famously said. But what kind of political order did he consider just? Upon which social strata did he propose relying to best organize life within the state? And what did he view as the key to proper and rational governance?