A science and its history -- Before Adam Smith -- Adam Smith -- The classical school : Thomas Robert Malthus and David Ricardo -- Consolidation and innovation : John Stuart Mill -- Karl Marx as an economic theorist -- The forerunners of marginalism -- The marginalist revolution I : William Stanley Jevons and Carl Menger -- The marginalist revolution II : Léon Walras -- Alfred Marshall and partial equilibrium theory -- Equilibrium and welfare : Edgeworth, Pareto, and Pigou -- Interest and prices : Knut Wicksell and Irving Fisher -- New perspectives on markets and competition -- The great systems debate -- John Maynard Keynes and the Keynesian revolution -- Frisch, Haavelmo, and the birth of econometrics -- The modernization of economic theory in the postwar period -- Further developments in the postwar period -- Long-term trends and new perspectives.