W HEN Aaron Director and Edward Levi launched the Journal of Law and Economics in 1958, Director suggested the title Law or Economics. This alternative title certainly described the world more accurately at that time: the traditional attitude of each discipline toward the other had been one of indifference. Only gradually has that attitude been replaced by a mixture of cooperation and hostility. The first systematic application in America of economics to law was the use of price theory to explain economic phenomena involved in the antitrust cases.' Director made creative use of price theory to explain phenomena such as tie-in sales and patent licensing and assisted younger colleagues such as John McGee and Lester Telser in their respective studies of predatory competition and resale price maintenance. In such applications, professional economic analysis was replacing the amateur economics of the lawyer. Lawyers did not welcome this development: the National Committee for the Study of the Antitrust Laws was the scene of a deep schism between the fifty-three lawyers and the eight economists.2 (These numbers probably represented the belief that 13 percent of antitrust policy is economics, the remainder law.) At one point, the lawyers attempted to exclude the economists completely from the formulation of the report. The division was not simply one between angels and legally trained devils. Consider the question of price discrimination. Economists insisted that price discrimination could persist only under noncompetitive conditions: under full competition, rivals would undermine any attempt to sell part of the supply at a higher price. The lawyers argued to the contrary: