My friend Alberto Alesina, the Nathaniel Ropes professor of political economy at Harvard, died of an apparent heart attack while on a walk with his wife, Susan, on Saturday. His loss comes a shock and a tragic blow to all who knew him and to a broad scholarly community. Less than eight hours before his death, he was corresponding with colleagues about ongoing research. It is hard to imagine the field of political economy without him.

Many in modern universities talk about the importance of interdisciplinary research. Many fewer devote their careers to it and in the process drive the creation of a new field that brings together scholars in previously separate fields. This is what Alberto did with the modern field of political economy.

I first met Alberto when he was a graduate student working on political impacts on the business cycle and issues around central bank independence in the 1980s. At the time, there were a few economists interested in understanding politics rather than telling politicians what to do. And there were a few political scientists interested in economic issues. But there was no academic field of political economy. Today, political economy is an important component of economics and political science. And Alberto deserves much of the credit. As much or more than anyone else, he showed what could be achieved by bringing economic analysis to bear on political questions.

Again and again, Alberto posed and answered important questions at the interface of politics and economics.

What institutional design can best control inflation? Alberto showed that independent central banks were the best way to control the political temptation to inflate.

Why do European countries have larger public sectors and more generous welfare states than the United States? In what were to be recurring themes in his work, Alberto, with collaborators, emphasized the importance of ethnic homogeneity in creating support for others, and the importance of cultural attitudes regarding the extent to which success and failure were deserved and under individuals’ control or were matters of luck. This work anticipated the conflicts within welfare states that are playing out today, particularly the heat surrounding immigration issues.

Why do governments run deficits? When do they embark on efforts to reduce them and what are the differing impacts of stabilization based on raising taxes and cutting spending? Alberto was at the forefront of global debates on these issues for the past two decades. He believed that in many circumstances, though certainly not all, austerity could stimulate an economy, particularly if it involved spending cuts rather than tax increases. His views were much less Keynesian than mine, and we disagreed often with some vigor. But I respected enormously his willingness to painstakingly accumulate data and his willingness to view it objectively.

Inevitably, as an Italian concerned with political economy, Alberto was deeply interested in and engaged with the European Union project. He recognized that making a return to war inconceivable after a thousand years of frequent conflict was one thing, while creating a United States of Europe was very much another. His insight into political economy led him to have strong views about how to balance the interests of the rich north of Europe and poorer south in a way that could work for both.

I saw how influential he was a few years ago when a group of economists were invited by the German political leader Wolfgang Schäuble to talk to the Group of Seven ministers and central bank governors about the future of Europe and global integration. Most of the Nobel Prize winners and former senior officials present were given seven minutes to speak on panels. Alberto gave the lunch speech. Schäuble was, as usual, wise: Alberto had the most valuable and useful insights.

Alberto did not just study politics and leadership, he lived it. He served for three years as the chairman of the Department of Economics at Harvard; he led to great effect and shrewdly, without unduly cutting into his beloved climbing and skiing time. He served as an editor of the Quarterly Journal of Economics as it evolved into the world’s most influential academic economics journal. For the past 14 years, he led the National Bureau of Economic Research program on political economy. A sub-discipline that had not existed when Alberto entered it became the focus of one of the most vibrant and substantial programs under his leadership.

Alberto and Susan had a wonderful and loving partnership. Their devotion to each other was evident to all in their circle. My heart goes out to her.

Whatever challenges he faced, Alberto Alesina always had a smile for others and an interest in what they were doing. He maintained his passion for adventure in the outdoors while keeping up a research pace that many of the most nerdy envied. He never appeared stressed even as he lived a bicontinental life between the United States and Italy. Some people make easy things hard. Alberto made hard things look easy.

Read more by Lawrence H. Summers