Karl Shell (born May 10, 1938) is an American theoretical economist, specializing in macroeconomics and monetary economics.Shell received an A.B. in mathematics from Princeton University in 1960. He earned his Ph.D. in economics in 1965 at Stanford University, where he studied under Nobel Prize in Economics winner Kenneth Arrow and Hirofumi Uzawa.Shell is currently Robert Julius Thorne Professor of Economics at Cornell University (succeeding notable economist and airline deregulator Alfred E.