As the primary lecturer for one of Harvard's most prominent Core courses, Martin S. Feldstein '61 is no stranger to campus life.

At the same time, in Washington, most know him better for his controversial tenure as a chief economic advisor in the Reagan Administration.

Indeed, the University's Baker professor of economics has straddled two worlds--a feat many insiders say has helped to make him a top contender for the Harvard presidency.

"[Feldstein] has been more successful than almost anybody else at combining distinguished scholarship and important involvement in economic policy," says Lawrence H. Summers, a Harvard economics professor currently serving as chief economist to the World Bank.

Whether as a professor, a top policy advisor or a regular columnist in The Boston Globe, Feldstein certainly draws attention. Alumni officials say that the 51-year-old economist, who was class marshal of his 25th reunion, is one of the most widely-recognized professors at Harvard.

Feldstein spent a two-year leave of absence in Washington, chairing the Council of Economic Advisers (CEA) from 1982 to 1984. During his time there, Feldstein sparred openly with other government officials over matters of economic policy.

"He is very much an independent thinker," says Lawrence B. Lindsey, a special assistant to President Bush who did his graduate work with Feldstein at Harvard. "Even when you disagree with him, you know that he has good reasons for thinking the way he does."

Feldstein is most well-known for his criticism of recent presidential deficit spending and his outspoken demands for tax increases. "He was drawing attention to the deficit as a problem before anyone else did," says Lindsey.

Feldstein was also one of the first policy analysts to make a connection between the deficit and currency exchange fluctuations. "He tends to be ahead of the curve in terms of seeing problems," Lindsey says.

Beyond his own policy insights, Feldstein left a significant institutional legacy at the CEA, according to some of his colleagues.

"I think he restored a lot of credibility to the CEA. There had been...the sense that the CEA was a bit of a cheerleader for the administration," says Lindsey. "He renewed a sense of respect for its independence."

Feldstein has been an outspoken critic of the present social security program; which he says discourages private savings. Instead, he favors an increase in private pension programs and a new system that does not rely on current workers' paychecks to fund an older generation's social security.

"Marty's a practical economist who recognizes and stresses the importance of incentives and of doing what's right for the long run, even if there is some pain in the short run," says the World Bank's Summers.

Although Feldstein's tenure in the Reagan Administration has tended to focus attention on his political persona, many Harvard watchers say that record is unlikely to affect his chances as a possible successor to outgoing President Derek C. Bok.

In fact, when Feldstein first made headlines by criticizing some Reagan economic policies from within, some observers said he did so with a Harvard audience in mind.