U.S. economist Martin Feldstein answers to reporters' questions during the conference in 2009. (RICCARDO DE LUCA/AP)

Martin Feldstein, a giant in the field of economics and an architect of President Ronald Reagan’s sweeping tax overhaul effort, died of cancer on Tuesday at age 79.

Feldstein was well known for his work on tax and spending policy and his three decades as president of the National Bureau of Economic Research. He also advised Democratic and Republican presidents.

“Marty was the pre-eminent bridge builder in the economics profession, someone who did more to bring people and ideas together in a congenial way than just about anyone else,” wrote Jeremy Stein, chair of the Harvard Economics Department, in a note to colleagues.

Feldstein had a long career in academia and public policy. He started teaching economics at Harvard University in 1967, a role he continued for half a century, taking only occasional breaks to serve the nation in various capacities.

From 1982 to 1984, Feldstein was chair of Reagan’s Council of Economic Advisers, helping write sweeping changes to the U.S. tax code, which passed in 1986.

A Republican, Feldstein was respected across the political aisle for his research and willingness to engage in deep intellectual debates about the leading public policy challenges of the day. He served on the President’s Economic Recovery Advisory Board during the Obama administration, helping devise ideas about how to get the nation out of the financial crisis and recession.

He also mentored students as diverse as Lawrence Lindsey, President George W. Bush’s chief economic adviser, and Larry Summers, President Bill Clinton’s treasury secretary. Tributes poured out on Twitter and on various economic email lists from people who said being one of Feldstein’s research assistants changed the course of their lives.

“Feldstein taught people a passion for economics and a passion for policy and not a particular political persuasion or slant. He was just as proud of his students who disagreed with him as he was with students that agreed with his perspective,” said Jason Furman, a former student and CEA chair under Obama.

Feldstein was also the winner of the John Bates Clark Medal in 1977, which was then awarded every other year to the person under 40 who made the most significant contribution to economics, a testament to his early prominence in the field.

A prolific writer, Feldstein wrote hundreds of scholarly articles as well as commentaries for a broader audience in The Washington Post, Financial Times, Wall Street Journal and other publications. In recent years, he warned the nation about the perils of rising U.S. debt and the folly of trying to reduce the trade deficit with China.

Many remembered Feldstein’s personal touch and wide network of contacts in academia, government and on Wall Street. He would often stop by the CEA to say hello to staffers and see how they were doing.

“He was obviously a brilliant man, but also one of the most generous and kind. He inspired so many generations of academics, policymakers and people who worked in industry,” said Derek Kaufman, a former research assistant of Feldstein’s in the mid-1990s who went on to become head of fixed income at the hedge fund Citadel.