The Italian sociologist, political theorist, and economist Vilfredo Pareto (1848-1923) is chiefly known for his influential theory of ruling elites and for his equally influential theory that political behavior is essentially irrational. Vilfredo Pareto was born in Paris on July 15, 1848. His father, an aristocratic Genoese, had gone into political exile in France about 1835 because he supported the Mazzinian republican movement. He returned to Piedmont in 1855, where he worked as a civil engineer for the government. Vilfredo followed his father's profession after graduating from the Polytechnic Institute at Turin in 1869. He worked as director of the Rome Railway Company until 1874, when he secured an appointment as managing director of an iron-producing company with offices in Florence.

In 1889 Pareto married a Russian girl, Dina Bakunin, resigned his post with the iron company for a consultancy, and for the next three years wrote and spoke against the protectionist policy of the...