Robert Lucas is one of the outstanding monetary theorists of the past hundred years. Along with Knut Wicksell, Irving Fisher, John Maynard Keynes, James Tobin, and Milton Friedman (his teacher), Lucas revolutionized our understanding of how money interacts with the real economy of production, consumption, and exchange.

Lucas's contributions are both methodological and substantive. Methodologically, he developed dynamic, stochastic, general equilibrium models to analyze economic decision-makers operating through time in a complex, probabilistic environment. Substantively, he...