"Waiting his time in the 1960s and early 1970s was, however, perhaps the most influential economic figure of the second half of the twentieth century. This was Milton Friedman (1912- ) of the University of Chicago, later of the Hoover Institution on War, Revolution and Peace, a diligent, even indefatigable, advocate of the policy that was to fill the post-Keynesian void, especially in the English-speaking countries. A small, vigorously spoken man, uniquely determined in debate and discussion, entirely free of the doubt that on occasion assails intellectually more vulnerable scholars, Friedman was, as he remains, the leading American exponent of the classical competitive market, which he held still to exist in substantially unimpaired form except as it had suffered from ill-advised government intrusion. Monopoly, oligopoly and imperfect competition played no important part in his thinking. Friedman was a powerful opponent of government regulation and government activity in general. Freedom, he held, was maximized when the individual was left free to deploy his own income as he wished. On the other hand, Friedman, unlike less sophisticated practitioners of his faith, was not wholly indifferent to the freedom that accrues from having income to spend. To this end, he was the author of the most radical welfare proposal in the years following World War II. The income tax, he proposed, should, as always, diminish to zero as the lower income brackets are approached. And then in the lowest brackets it should return income, the amount increasing with increasing impoverishment. This was the negative income tax, a secure minimum income for all. Not many economists of the left could lay claim to such an impressive innovation. Friedman's central contribution to the history of economics was, however, his insistence on the controlling influence of monetary action on the economy and specifically on prices. After a lag of a few months, prices, he held, would always reflect movements in the money supply. So if one controlled the money supply limited its increase to the slowly expanding requirements of trade, the T in Fisher's historic equation prices would remain stable. In a statistically impressive demonstration, Friedman, in company with Anna Jacobson Schwartz, sought to show that this relationship had held, or appeared to have held, long in the past. So, presumably, it must in the future."