West German historian Fritz Fischer, vilified and ostracized in 1961 after his landmark book on pre-World War I German war policy, received three standing ovations this week at a conclave here of the American Historical Association.

Some 5,000 historians gathered for the 102nd annual meeting of the association. Participants, who chose among 135 sessions ranging from the development of jazz in Europe to the question of Hitler's "missing" policy paper on genocide, saved their greatest enthusiasm for the 79-year-old Fischer, now professor emeritus at the University of Hamburg.

Fischer's book, published 25 years ago, once drew criticism because it insited that Germany had been planning an assault on Western Europe since 1892. Fischer, who was widely blamed for the "new war guilt" debate that swept the country, told a panel here that the West German government canceled a planned trip to the United States in 1964 because of pressure from such historians as Gerhard Ritter.

His book in particular disputed the theory that Germany was coerced into war through pressures from its allies. Fischer made the West German public aware that the nation's military and diplomatic policy was highly aggressive. Germany, he said this week, still needs to face up to its past and accept its role in the European wars of the 20th century.

The topic "Jazz in Society and Politics: Europe, 1918-45" represented the first time jazz made it onto the program. On the question of "Genocide as Social Policy in Nazi Germany," a panel agreed that the search for a written order from Hitler directing extermination policies had been fruitless because Hitler did not want it documented. Henry Friedlander, professor of history at Brooklyn College, pointed out that a precedent existed in the Weimar Republic, where sterilization and euthanasia were practiced on a limited basis, mainly on the mentally handicapped.

The AHA meetings, which conclude today, were convened at the Sheraton Washington and Omni Shoreham Hotel. The job register for teaching positions was as small as it has been since 1976, with only 83 posted listings for interviews. The book exhibit was voluminous, with displays from more than 100 publishers.

The newly elected president of the association is Akira Iriye of the University of Chicago.