Sixty-one years after his hallmark book “Economics: An Introductory Analysis” was first published, Paul A. Samuelson, the first American to win the Nobel Prize in economics, died in his home on Sunday after a brief illness. He was 94.

Samuelson, who helped to popularize the introduction of Keynesian economics to Americans, attended college at the University of Chicago and was a three-time alumnus of the Harvard Graduate School of Arts and Sciences.

He was a member of the Harvard Society of Fellows—a University group aimed to “give men and women at an early stage of their scholarly careers an opportunity to pursue their studies in any department...free from formal requirements,” according to its Web site—before obtaining his professorship at MIT in 1940.

Samuelson was best known for his incorporation of mathematics in understanding economics.

“He was interesting as a kind of mathematical economist because his style was unusual,” said Economics Professor Martin L. Weitzman, a former student and colleague of Samuelson. “He didn’t really prove stuff rigorously, but it was more like a sketch of a proof... He would translate everything to his own image model in his head and into his own terminology.”

Weitzman remembers sitting next to Robert M. Solow ’44, a Nobel laureate compatriot at MIT, when Solow recalled a book he had read several decades ago.

“You seem to remember the title of every book that you’ve ever read,” Weitzman said to Solow.

“That’s true, more or less, but Paul [Samuelson] here remembers what’s in every book he’s ever read,” Solow said.

Weitzman said that Samuelson was just as engaging in a social context.

Weitzman noted that when Samuelson won the Nobel Prize, he was reminded to take his acceptance speech seriously.

“He was prone to tell stories and became too entertaining sometimes,” Weitzman said.

In addition to his academic achievements and social charisma, Samuelson’s colleagues remember his care toward his students, despite his high-profile reputation.

“He was one of the most generous persons I knew in the economics profession and in his attitude toward younger economists,” said Economics Professor Benjamin M. Friedman ’66. “He always went out of his way to be encouraging, to tell people how much he liked what they were doing.”

Friedman added, “People who did not know Samuelson personally will miss his steady flow of important creative ideas.”

In 1979, Samuelson published a research paper in the Journal of Banking and Finance entitled “Why We Should Not Make Mean Log of Wealth Big Though Years to Act Are Long.”

The entire article, as the title suggests, was written using only words that were one syllable long, except the last word, which was “syllable.”

“It’s just no other economist had such a combination,” said Weitzman. “You’re not going see the likes of him again soon.”

—Staff writer Xi Yu can be reached at xyu@college.harvard.edu.