This afternoon, new graduates of Harvard’s Kennedy School of Government will be sent into their public-service careers with guidance from one of academia’s leading global thinkers.

Lamont University Professor Amartya K. Sen, who won the Nobel Prize in 1998 for contributions to welfare economics, will deliver the Class Day address at the Kennedy School today. He rejoined the Harvard economics department in January after spending nearly six years as master of Trinity College, Cambridge—a post he garnered after recommendation by the British prime minister.

According to Kennedy School Senior Associate Dean Joseph McCarthy, Sen’s selection as this year’s speaker reflects the Kennedy School’s increasing emphasis on Harvard’s role as an international educator.

“The Kennedy School is the most international school at Harvard,” McCarthy says. “We estimate that between a third and 40 percent of our current students are following a path that will lead them toward of international development.”

Both international enrollment and enrollment in internationally oriented degree programs have increased in recent years, he says, largely as a result of a heavy emphasis on the program from outgoing Dean of the Kennedy School Joseph S. Nye.

Sen’s academic career, which has centered on economic and moral dilemmas resulting from underdevelopment in the international context, made him an ideal speaker to usher out the Kennedy school graduates as they embark on internationally oriented careers.

Last year, Massachusetts Governor W. Mitt Romney delivered the Kennedy School’s address.

Sen is no stranger to the Commencement stage. He delivered Harvard’s main Commencement address—the most prestigious speech in the ceremony—in 2000. Even while teaching at Trinity College, he frequently made visits to speak at Harvard.

Sen’s address this afternoon, geared toward the Kennedy School’s emphasis on international development, will be titled “A Democratic World.”

Sen first rose to prominence in the 1960s and, in the years since, has led a new wave of economic theory based on concern for the human implications of financial pressures on disadvantaged populations.

Finding a common thread in the economist’s work, though, is difficult. Pursuing a variety of projects over the course of his career, Sen has veered increasingly from his own field and into others. His intellectual hallmark, colleagues say, has become the intense interdisciplinary quality of his work—a trajectory that has drawn him outside the traditional boundaries of his field and into politics and philosophy.

“Amartya Sen is a hero to those of us who would recall economics to its roots in moral and political philosophy,” Bass Professor of Government Michael Sandel writes in an e-mail. “He reminds us that economics can be a humane science, concerned not only with utility but also with human development, democracy and freedom.”

Sen’s recent activities on campus—even during the five years when he was master of Trinity College—reflect his broad and socially oriented interests.

In addition to speaking at the University’s 2000 Commencement, he also lectured at the Inaugural Lecture Series at the Radcliffe Institute of Advanced Study in 2001. In a 2002 Institute of Politics Forum, he debated University President Lawrence H. Summers on the implications of globalization after Sept. 11—although the two economists differed little in their basic opinions on the topic.

In addition to his ample academic duties, Sen has also been the honorary president for OXFAM, a global organization that works to overcome poverty. He now serves as OXFAM’s honorary adviser. For both his academic work and his humanistic concerns, he has accumulated a long list of honors.