I FIRST came across the name and work of Henry Simons when I went to Harvard as a graduate student in 1947. My previous training at Toronto and Cambridge had given me the impression for various reasons that the sole intellectual force at Chicago was the Canadian scholar of the history of thought Jacob Viner, though one was dimly aware-largely through the anecdotage of Harold Adams Innis at Toronto-of the existence of another Chicagoan, Frank H. Knight, who dabbled irrelevantly but rather amusingly in the philosophy of our subject. At Harvard, Alvin Hansen made us read the monetary writings of everyone active in the field since the turn of the century; and that included both Simons and Mints and a young firebrand called Milton Friedman. We became aware of the fact that some people thought that money mattered; and in particular that Simons thought it mattered so much that it should be subjected to a one hundred per cent reserve requirement and managed by open market operations so as to preserve price stability. But, Harvard being the centre of Keynesian economics in the United States that it then was, we were left in no doubt that having to read Simons, Mints and Friedman was intended merely to instruct us in the density of the opposition that modern scientific economics was up against. It was not until I met Friedman in person, as a visiting colleague at Cambridge -a traumatic intellectual experience for myself and the only two other Cantabrigians who were willing to expose themselves to the moral risks involved, and which ultimately brought me as a pilgrim to Chicago-that I began to appreciate what a powerful intellectual force Simons had been, especially as a teacher, both on the "Chicago School" (if I may use that term without offending George Stigler) and on American economics generally; and also how deep were his insights into the fundamentals as distinguished from the transient surface phenomena of economic policy-making. I am honoured indeed to have been invited to give the Henry Simons Lecture this year.