No living American satirist has pushed the limits of satire--perhaps the most extreme form of expression that society has tolerated--further than Garry Trudeau, who draws the comic strip "Doonesbury." Newspaper editors regularly pull the strip, alter it, or accompany it with a disclaimer when they think it is unfair or libelous. And the public figures he satirizes frequently react with public indignation. In order to understand their reactions better, a study examined the content of Trudeau's controversial strips over two decades. Findings showed that though Trudeau frequently makes political commentary, he also satirizes social issues which other comic strip artists would consider too sensitive, i.e. Congressional sex scandals, vigilante killers, drug use, revolutions in foreign countries, and unmarried couples living together. Trudeau's satire constantly tests the limits of taste, fairness, and appropriateness. But that is what satirists are supposed to do: direct their own incredulity, anger, or morality at whatever most outrages them. While "Doonesbury" regularly tests the limits of satire, and frequently goes over the line of taste, its popularity is strong enough for now so that the strip has lost little of its bite. (One hundred and four notes and 13 figures are included.) (MS)