It's full of ghosts," says Harry Woolf, gesturing to the restored 17th-century farmhouse where he lives. It is the official residence of the director of the Institute for Advanced Study in Princeton, N.J. Woolf's statement may not be the most scientific ever uttered at the institute, the grandfather of U.S. think tanks, which marked its 50th anniversary May 20. Two things seem certain. If there are ghosts, they are extraordinary (Albert Einstein, T.S. Eliot, et al), and they should be more tranquil today than they were four years ago, when Woolf became director. Then the institute was embroiled in a bitter dispute over expanding its faculty to include more social scientists.

Woolf, 56, now says, "The wars are over. Whether there is scar tissue or healthy tissue over the wounds would be presumptuous to say. But people who were cool are increasingly warm in their interactions."

The institute is unique among the great centers of learning in the world. Begun with $5 million from department store tycoon Louis Bamberger and his sister Caroline, it is devoted to the study of nothing in particular and the universe in general. The 30 permanent faculty members—all men—receive a reported $40,000 a year whether they read, write, think or play croquet. There are no classes to teach; the appointment is for life (although at 70 the professors go on emeritus status). Einstein, physicist J. Robert Oppenheimer, mathematician John von Neumann and art historian Erwin Panofsky are among the geniuses who died while working at the institute.

There are also 175 or so visiting members, most of whom spend a year at the institute, mingling with the regulars or not, as they choose. (Eliot wrote part of The Cocktail Party there in 1948.) "If one of the scholars wants to go into a new discipline, he doesn't have to clear it with anyone," says Woolf. "He might make a great contribution or a fool of himself. The security of this place becomes a means of generating the free flow of the mind."

When Woolf arrived in 1976, after 15 years on the faculty and as provost at Johns Hopkins University, the institute was generating mostly heat. Carl Kaysen, an economist who succeeded Oppenheimer as director in 1966, had tried to expand the social sciences department. The math-history clique angrily sniped at a Kaysen nominee. When he went to the trustees to override a faculty veto of the appointment, the clamor intensified. Kaysen finally quit.

Woolf, the Brooklyn-born son of Russian and Polish immigrant parents, studied physics and math before specializing in the history of science. "I see my own life," he says, "as integrative in nature." To emphasize his eclecticism, he serves as chairman of the board of the Universities Research Association of the Fermi Lab in Batavia, Ill. and as a member of the board of governors at Tel-Aviv University. He is also a co-founder of the Johns Hopkins Program for International Education in Gynecology and Obstetrics.

In addition to his peacemaking, Woolf has also improved fund-raising. The institute's annual budget of $8 million is met only partially by the income from its $70 million endowment. Donations and grants make up the rest. In 1977 Woolf opened a faculty pub in the dining hall to encourage socializing. It's known as "Harry's Bar." More important, he persuaded the faculty to accept an expanded social science school. "I do not know what one professor thinks of another and I need not," he says. "There's enough of a system to protect one from another, without much flimflam."

Physicist Freeman Dyson, who joined the faculty in 1953, minimizes the old disputes, calling them "the squabbles of a small group of old men." He welcomed Woolf. "I admire what he is doing—getting the institute on its feet financially," says Dyson. He has a ready answer when asked if Woolf is controversial. "No, I don't think so." At an institution which once got too much publicity for the wrong reasons, that kind of quiet leadership may be just what the doctors ordered.