There has been a particular way of looking at crowds in every period of history. Explicit, self-conscious, theoretical interest in ‘the psychology of the crowd’, however, is recent. The attempt to construct an exact theory of crowd behaviour dates from 1870, and crowd theory had to wait until 1960 for its first masterpiece, Canetti’s Crowds and Power. Histories of political thought concentrate on a succession of justifications for forms of rule. What is to be ruled, the crowd, and what threatens rule, the mob, figure only on the sidelines. If the crowd gets in at all, what a particular thinker has to say about what it is like is either accepted at its face value, or dismissed as bias. Histories of political thought are written from the top looking down; by this I do not mean that historians of political thought are always ‘on the side’ of rulers, though a case could be made out for that; what I mean is that by attending to justifications for forms of rule, historians of political thought have usually failed to see that justifications for forms of rule are made that much more convincing if the ruled can be made out to be at best a crowd, therefore needing to be ruled, or at worst a mob, therefore threatening rule.