The American Newspaper Association's 1986 compilation of 45 newspaper antitrust actions filed since 1980 revealed that the majority of antitrust actions during that period involved disputes over advertising practices. The federal government was virtually absent in its enforcement of antitrust laws against newspapers. About one-third of the completed actions actually went to trial (of a sample 13 cases, only two were won by the plaintiffs). Specific allegations included predatory prices (the complaint in about two-thirds of the cases), collusion, price discrimination, tying, refusals to deal, and mergers. An important issue in antitrust cases was the definition of the relevant market, which has both a product and geographic dimension. Before 1980, legal precedent favored a very narrow product and geographic definition of the market within which newspapers operated. Since that year, all five courts of appeal rulings and eight of nine district court rulings have been consistent with this narrow definition. A broader definition would make antitrust enforcement in the newspaper industry even more difficult. Recent actions have been consistent with the predominant view that newspapers provide a service to readers and advertisers, that they are not simply a commodity of paper and ink. An analysis of predation actions, the most common recent charge, suggests that many antitrust actions may be brought to stifle competition rather than to protect it. Further in-depth studies of newspaper antitrust actions are called for. (One table of data and 22 references are included.) (AEW)