Swiss economist and historian who warned against the perils of unchecked industrialism. His pioneering theories on the nature of economic crises and the risks of limitless competition, overproduction, and underconsumption influenced such later economists as Karl Marx (Marx, Karl) and John Maynard Keynes (Keynes, John Maynard).

Sismondi became a clerk in a bank in Lyon, France, at age 16 and witnessed the unfolding of the French Revolution. To escape the Revolution's spreading effects, he and his family went in 1794 to Tuscany, where they became farmers. Sismondi's experiences and observations there resulted in Tableau de l'agriculture toscane (1801; Picture of Tuscan Agriculture). Living in his native Geneva from 1800 on, he became such a successful author of books and essays that he could decline offers of professorships.

Sismondi's monumental 16-volume Histoire des républiques italiennes du moyen âge (1809–18; History of the Italian Republics in the Middle Ages), which regarded the free cities of medieval Italy as the origin of modern Europe, inspired the leaders of that country's Risorgimento (nationalist unification movement).

As an economist, Sismondi was at first a loyal follower of Adam Smith (Smith, Adam), the proponent of laissez-faire economics. His Nouveaux principes d'economie politique (1819; “New Principles of Political Economy”), however, represented a break with Smith's ideas. Sismondi argued for governmental regulation of economic competition and for a balance between production and consumption. He foresaw a growing rift between the bourgeoisie and the working class—coining the term class struggle—and called for reforms to ameliorate the living conditions of the latter, though he stopped short of condemning private property.