The world of demography has lost one of its most influential figures.

James V. Vaupel had a career that spanned more than two continents. He held regular appointments at major academic institutions in four countries. Over more than four decades, he was at the center of a network of researchers for which he was the magnet, the glue, the inspiration, the leader and the visionary.

I first met Jim in 1985. It was the summer after my first year in graduate school at Princeton. With a cohort of other young demographers, including Zeng Yi and Andy Foster, I spent the summer in Vienna as a participant in IIASA’s young scientists summer program (YSSP). IIASA’S population program at that time was headed by Nathan Keyfitz, who had been my inspiration to become a demographer.

IIASA’s summer program in population in 1985 was co-led by Jim Vaupel and Anatoli Yashin. This was still the era of the Cold War, and the collaboration between Jim and Anatoli was pathbreaking. For me, it laid the foundation for a long and close collaboration with Russian colleagues, including Vladimir Shkolnikov, Kirill Andreev, Dmitri Jdanov and Liudmila Andreeva. For the field of demography, it helped lay the foundation for a European school of demography, in which the Max Planck Institute for Demographic Research has played a pivotal role.

It was during that summer in 1985 that I began to work with large arrays of historical mortality data organized by age, sex and time. Jim Vaupel shared with me mortality data sets for Italy, France and Sweden that he had received from Graziella Caselli, Jacques Vallin and Hans Lundström. Those three, together with Shiro Horiuchi and others, were my key collaborators and partners in the early days of my career. Thanks in large part to Jim, we came together as part of a vibrant community of researchers exploring mortality at older ages, with a particular emphasis on extreme longevity, not only in humans but also in nematodes, fruit flies and even light bulbs.

In the current year, we are celebrating the 20-year anniversary of the Human Mortality Database, which was launched at the annual meeting of the Population Association of America in 2002. The HMD was preceded by two smaller projects known as the Berkeley Mortality Database and Kannisto-Thatcher Oldest-Old Mortality Database, which had been developed in the 1990s at the University of California at Berkeley and at the Max Planck Institute for Demographic Research, respectively. From my perspective, although it was launched formally in 2002, the seed for the HMD project was planted in 1985 when Jim Vaupel gave me my first opportunity to work with such data.

Jim’s generosity toward me as a young researcher was formative. His philosophy of openness in sharing data inspired my own commitment to building and sharing data resources. He was also the person who introduced me, in the summer of 1985, to the methodological challenges of the age-period-cohort identification problem, which became the central topic of my PhD dissertation.

My close interaction with Jim Vaupel continued for many years after we first met at IIASA in 1985. I had the pleasure of knowing his wife, Bodil, and his two daughters, Anna and Sophia, over many years, and I have fond memories of visiting their home in Kerteminde and making music with his daughters. Although I maintained my independence and, surprisingly, was never his co-author, I have never felt far from Jim’s inner circle. Throughout his career, whether at IIASA, Minnesota, Odense, Duke, or Rostock, I was frequently in contact with Jim, and I know he often worked behind the scenes in ways that were critical during my early career. It goes without saying that the HMD project would never have been the success that it has become without Jim’s steadfast support over many years.

Thanks to Jim Vaupel, I also had the honor of knowing Christian Mortensen, for several years the world record holder for male longevity (he died in 1998 just shy of 116 years old). Jim’s Danish colleagues, in particular Bernard Jeune and Axel Skytthe, provided the tip that Mr. Mortensen was living in a Danish-American nursing home in San Rafael, California. Mr. Mortensen had immigrated to the U.S. from Denmark in 1903. Based on documentary evidence gathered on both sides of the Atlantic, we were able to confirm numerous details that Mr. Mortensen told me during interviews that I conducted during my periodic visits to the nursing home.

Jim’s fascination with the «oldest-old», and especially with super-centenarians, was legendary. He loved to tell the story of his most recent encounter with a person of exceptional longevity. Jim would point to the sky and share the latest pearl of wisdom that he had gathered on these adventures. One that I remember vividly — «Don’t eat tomatoes!»— was no more unusual or unexpected, or less likely to be correct, than the others.

For me, Jim’s example and influence as a scholar went beyond our shared interest in the health and mortality of older persons and the phenomenon of extreme longevity. For me, a crucial and defining element of Jim’s career was his commitment to public policy and his belief in the importance of demographic analysis as a guide to policy making. Jim earned his PhD from Harvard’s Kennedy School of Government. His post at the University of Minnesota in the late 1980s was in the Hubert Humphrey Institute of Public Affairs, and his subsequent affiliation with Duke University was in the Sanford School of Public Policy.

I left the University of California at Berkeley in 2013 to become the Director of the Population Division of the United Nations. I have never known with certainty how this career move was seen by my senior colleagues. Recently, however, I received a message from Jim that touched on this topic.

In November 2021, we were both invited speakers in an online remembrance of the eminent Russian demographer, Anatoly Vishnevsky. Jim’s presentation was very technical, on a topic that I had worked on many years before. For my part, I provided a preview of a major report that we were close to finalizing at the United Nations, Global Population Growth and Sustainable Development, which examines the challenges of the continuing, rapid growth of the human population.

I wrote to Jim shortly after the event to offer a few comments about his presentation. He wrote back, thanking me for my insights on his work and offering these words of encouragement: «I enjoyed your masterful policy-relevant overview today. You hold an important position and are doing an outstanding job». I know he really meant it too, and that means so much to me in this moment. That was the last time I heard from him.

Thank you, Jim Vaupel! You gave us wings and made sure that we would learn how to fly. We will be forever grateful for all that you have given to the field of demography.