Vilfredo Pareto was an Italian economist, sociologist and engineer whose work influenced modern economics and social theory. Born in Paris in 1848, he trained as an engineer before working in industry and later turning increasingly to economics. In 1893, he succeeded Léon Walras as professor of political economy at the University of Lausanne, where he developed mathematical approaches to economic choice and equilibrium.

Pareto is associated with the concept of Pareto efficiency, in which no person can be made better off without making someone else worse off. His studies of income and wealth distribution also contributed to what became known as the Pareto distribution and, later, the Pareto principle. In sociology, his Trattato di sociologia generale examined non-logical action and the circulation of elites. His work helped establish the Lausanne School as an important centre of mathematical economics and influenced later debates in welfare economics, political sociology and theories of elites.