Knut Wicksell
Knut Wicksell, Swedish economist, was one of the founders of modern macroeconomics. His work focused on real and nominal interest rates, the marginal productivity of capital, and determinants of the price level. He elaborated on ideas from economists as broad-based as Jevons, Böhm-Bawerk, and Clark, and influenced economists from Irving Fisher to John Maynard Keynes to James Buchanan. [The image comes from “The Warren J. Samuels Portrait Collection at Duke University.”]