# Aaron Director The economist who taught antitrust to the lawyers who dismantled it. Director published almost nothing, and is arguably the most consequential figure in twentieth-century American antitrust. At the University of Chicago Law School from 1946, he co-taught the antitrust course with Edward Levi — Levi presenting the case law, Director then explaining why the economics of each holding was wrong. He founded the *Journal of Law and Economics* in 1958, creating the venue where the argument could be built. His students and interlocutors include [[Robert Bork]], [[Richard Posner]], Ward Bowman, John McGee, and Frank Easterbrook; [[Milton Friedman]], his brother-in-law, credited him with reshaping his own thinking. The signature move is the **single monopoly profit** theorem: a firm with a monopoly in one market generally cannot increase its total profit by leveraging into a second, so tying and vertical restraints are more likely explained by efficiency than exclusion. That argument, worked out in a seminar room, is what eventually dissolved the per se rules and produced the [[Consumer Welfare Standard]]. Also a founding participant in the Mont Pelerin Society and the person who arranged American publication of Hayek's *The Road to Serfdom*. See [[Chicago School]]. > Stub — fill out. See [[US Antitrust and Monopoly Timeline]].