Gustave Le Bon was a French doctor and sociologist and a pioneering figure in social psychology. After completing medical studies in Paris he traveled extensively and wrote on a variety of topics ranging from premature burial to equitation. His interests then turned to anthropology and psychology. Beginning in 1902, his Wednesday luncheons attracted the Parisian intellectual and social elite. In The Psychology of Peoples (1894), Le Bon posited that emotions such as honor, nationalism, and religious faith (rather than reason) drive social evolution. Over time, exposure to institutions, laws, and habits creates racial or national character. Today he is known primarily for The Crowd: A Study of the Popular Mind (1895). Crowds are credulous, unpremeditated in their actions, and untrustworthy as a source of reliable testimony. The crowd’s “collective mind” responds to suggestions more readily than the individual minds of its members, hence its “servility” in the face of strong authority. Its “soul” is determined by three factors: (1) its number; (2) the force of contagion or imitation; and (3) hypnotic suggestion. Le Bon analyzed different kinds of crowds, including criminal crowds, electoral crowds, and parliamentary assemblies. Edward Bernays, widely regarded as the father of modern advertising, drew heavily on Le Bon’s work when formulating his ideas on propaganda and mass manipulation.