Vilfredo Federico Damaso Pareto was a famed economist and sociologist. He is best known for the economic concept of Pareto efficiency (or Pareto optimality). He made other wide-ranging contributions to economics that since the late 1930s have greatly influenced modern conceptions of demand, welfare, and planning. Pareto's law asserts that distribution of income and wealth follows a regular logarithmic formula. (Pareto charts are a standard statistics display tool.) He also made important contributions to sociology and moral philosophy.

Vilfredo was the only son of a nobleman, who was living in Paris in exile from Genoa for his nationalist views, and a Frenchwoman. The family returned to Italy, where the elder Pareto worked as an engineer. He made a comfortable living raising his family in a middle-class ...