In 1988 Marshall initiated a gender-bias study with two other lawyers, which found that women lawyers, are paid less and receive less respect than their male counterparts. The influential study prompted the SJC to form its own gender-bias investigating unit the following year.

Marshall served as president of the 8,000-member Boston Bar Association from 1991 to 1992, as the group's second woman chief. She pushed for greater access to the courts for poor and middle-class citizens; and in 1992, she helped draft a BBA legislative package that would have transferred appointment and budgeting power from the state legislature to the state's chief justices. That plan was ultimately derailed on Beacon Hill.

Marshall sits on the board of directors of the American Civil Liberties Union of Massachusetts.

The nomination to the state's top bench didn't come as a surprise: Marshall's name had been tossed around ever since Chief Justice Paul J. Liacos announced his retirement in June.

Still, when Marshall called President Neil L. Rudenstine Tuesday morning to inform him of the nomination, "it's really with sweet sadness that I told him," she said in an interview.

Rudenstine described Marshall's work as "totally superb."

"She's just been extraordinary from every point of view, a wonderful person and an exceptional mind, a person who understands the institution, knows the law but also knows the limits of the law," he said.

At Harvard, Marshall helped draft the University's policies regarding the sharing of student financial-aid information with other schools, in the wake of a 1989 Justice Department ruling that such sharing among the Ivy League universities amounted to anti-competitive price fixing.

Marshall also developed briefs the University planned to file in the Hopwood suit against the University of Texas challenging affirmative-action in higher education. Ultimately, the case never reached the Supreme Court, but Marshall's research will be used "when the next one comes," Rudenstine said.

But as Harvard's head litigator, Marshall's biggest defeat was handed to her in September 1993, when Harvard Law School settled a sex-discrimination case with former Assistant Professor of Law Clare Dalton.

The Law School conceded no fault, while agreeing to pay $260,000 to fund an institute for the study of domestic violence. Still, Dalton--a proponent of the Critical Legal Studies movement in law who had been denied tenure in 1987--called the settlement "a vindication" of her claims and got a one-time cash award of $80,000 to head the institute.

And earlier, in August 1993, the University came under fire after the release of a report that said allegations of racial and gender discrimination in the Police Department's security-guard unit were "unfounded." The report--which was authored by two University lawyers and a former colleague of Marshall's at Choate, Hall & Stewart--did identify "management weaknesses" in training and communication, but it was roundly criticized by the guards, who disagreed with its findings.

Rudenstine defended Marshall's handling of the report. "It was a situation that was looked at well and handled well," he said.

Others are less charitable. "Everybody knew that there were serious problems of racism in the Harvard University Police Department, but I think that Margaret Marshall played down those problems in the interests of administrative harmony," said Harvey A. Silverglate, a Boston lawyer who has represented two Harvard students in legal actions against the University.

Marshall shied away from a public role, rarely talking to the campus media or directly with students.