Little by little, that has been changing. Yeshiva students like Tzvi Feifel, a 23-year-old senior and the book fair’s chief executive, now live among the neighborhood’s Dominican families and other immigrants, not just in the gentrified quarter west of Broadway, but also in the buildings along the avenues to the east and near the university’s spine on Amsterdam Avenue between 183rd and 187th Streets.

Wider community events, like the swearing-in last month of State Senator Adriano Espaillat, are often held in the university’s theaters. Two years ago, Rabbi Yosef Kalinsky, an assistant dean, joined Community Board 12 in Washington Heights, and last summer, he helped organize a family picnic for the board’s 50 members in Fort Tryon Park. Ebenezer Smith, the board’s district manager, said the university was increasingly employing neighborhood residents.

“They understood that they need to have more community presence,” Mr. Smith said. “They’re not where Columbia University is, which sponsors many things, but little by little they want to get there.”

Part of what kept Yeshiva students apart from the greater community for many years was fear of crime, which seemed to be an almost-daily presence in an era of turf wars over drug sales.

Terry D. Novetsky, 52, of Teaneck, N.J., is a 1980 graduate of Yeshiva and a partner at the Manhattan law firm of Kaye Scholer. He recalled that on his first day as a freshman from Michigan, he came across police officers examining a body at 186th Street and Amsterdam Avenue.

Sunday, Mr. Novetsky was at the fair to pick up a book about Rabbi Joseph Soloveitchik, the fabled philosopher of Orthodox Judaism and the former head of Yeshiva’s rabbinical school. Mr. Novetsky brought along his daughter, Tamar, 16, who wanted to find a cookbook for her mother.