This text organizes cases over four periods: a 25-year period from 1890 to 1914, in which most of today’s issues were foreshadowed; a 25-year period from 1915 to 1939, in which the ‘rule of reason’ forced courts to investigate the actual consequences of business practices; a 35-year period from 1940 to 1975, in which the per se rule and industry concentration provided the predominant models for analysis; and the modern period of over 40 years, which is a synthesis of the second and third periods. The new Sixth Edition expands upon the recent developments in antitrust policy. All major Supreme Court authority is covered, including the 2016 North Carolina Dental opinions, as well as the 2010 Merger Guidelines, developments in lower court treatment of tying, bundled pricing and mergers, and the dramatic changes in antitrust law and policy the Democratic Party proposed as part of its 2017 Better Deal.