Pulitzer Prize-winning historian Barbara Tuchman confessed to more than 2,000 librarians that she rarely reads contemporary nov els. "The behavior is so aberrant and the characters are so unpleasant," Tuchman said. "The subjects all seem to be crime, murder, incest." Tuchman's speech Wednesday kicked off the national four-day conference of the 6,000-member Public Library Association in Pittsburgh. "The public, in general, seems only interested in reaching for its daily serving of trash," she said. Tuchman, 76, won the Pulitzer Prize for "The Guns of August" and "Stillwell and the American Experience in China."