Cowles Professor of Government Judith N. Shklar, an eminent political theorist and the first woman to be granted tenure in the Government Department, died early yesterday morning from a heart attack suffered last week. She was 63.

Shklar, a Cambridge resident, was a distinguished scholar and teacher of the history of political thought, notably that of the Enlightenment period. Her studies spanned the range of ideas at the intersection of political theory and literature.

Shklar's colleagues in the Government Department described her as a "towering figure in her discipline" and an "absolutely devoted teacher."

"One often calls people irreplaceable, but she really is an absolutely unique combination of erudition and extraordinary scholarship in political theory," said Dillon Professor of the Civilization of France Stanley Hoffman. "She has trained generations of undergraduates, graduates and teachers."

Hoffman, a close friend and colleague, once called her "the most devastatingly intelligent person I ever knew here."

Shklar was hospitalized in Concord, N.H. last Friday after a heart attack during a family vacation. She was transferred Sunday to Brigham and Women's Hospital in Boston, where she died at about 3 a.m. yesterday morning.

She is survived by her husband, Gerald, who is Brackett professor of oral pathology at the Dental School, and three children, David, 37, Michael, 32, and Ruth, 27.

Born Judith Nisse in Riga, Latvia, she and her family traveled across the former Soviet Union in the early part of World War II just before Latvia was annexed. The Jewish family fled both Stalin and Hitler and eventually landed in Sweden and Japan.

The family flew to Seattle shortly after the bombing of Pearl Harbor in December 1941, and were jailed for being non-U.S. citizens travelling from Japan. Shklar's father, an international banker, was able to secure their release through contacts in New York.

The family then moved to Montreal, where sheattended McGill University and married her husbandat the end of her junior year.

She received her doctorate at Harvard in 1955,and joined the faculty the year after. Shereceived tenure in 1970 at the age of 42, and wasawarded the Cowles professorship in 1980.

She authored a number of books, includingAfter Utopia (1957), Legalism(1963), Men and Citizens (1969), Freedomand Independence (1976), Ordinary Vices(1984) and Montesquieu (1987). In addition,several collections of her lectures have beenpublished.

"She defended a version of liberalism notrooted in absolute philosophy but rather in theoverriding imperative to avoid cruelty, violenceand injustice," said Professor of GovernmentMichael J. Sandel. "For her, the point of politicswas not to achieve the highest human ideals, butrather to avoid the gravest of human evils."

Stanfield Professor of International PeaceRobert O. Keohane, who was a student of Shklar'sin the early 1960s, said her work in the "eloquentdefense of liberalism" could be explained in termsof her experience; she was not one to take liberaldemocracy for granted.

"To people who knew her, she was a cure forintellectual arrogance. She knew so much, and wasso much smarter than everyone else, that shereally stood out," he said.

"She was one of the most powerful teachers onecould hope to encounter. She left an enduring markon everyone she came in contact with," he said.

Shklar, who was on leave this fall, developedand taught Moral Reasoning 42, "PoliticalObligation." She was scheduled this fall to teachGovernment 1080. "American Political Thought."

"She took such a tremendous interest in herstudents," said Shattuck Professor of GovernmentPaul E. Peterson. "Above all, she will beremembered for her dedication to her students."

Shklar has lectured at a number of universitiesaround the world, including Oxford, Cambridge,Hebrew University, and the Van Leer Institute.

Among other awards, she won a MacArthurFoundation "genius grant" in 1984. Shklar waselected president of the American PoliticalScience Association in 1989.

Funeral services have not been arranged yet. Amemorial service at Harvard is scheduled forNovember 6