As the economists and lawyers contributing to this volume demonstrate, an important element of the Reagan Revolution has been a fundamental shift in antitrust policy and enforcement away from the focus on market structure during the 1960s and early 1970s toward a greater emphasis on the effects of business conduct on economic efficiency and consumer welfare. This shift, caused both by a marked change in the political climate and changes in the thinking and research output of economists, has had an enormous impact on the volume and substance of antitrust activity during the 1980s. The...