In Memory of William P. “Bill” Butz (1943–2025)

With great sadness, we remember the life of William P. “Bill” Butz, an renowned economist, demographer, and cherished member of the IIASA community.

Bill's career spanned research, leadership, and public service, with roles at the RAND Corporation, the U.S. Census Bureau, the National Science Foundation, and as President and CEO of the Population Reference Bureau. His expertise in demography and economics shaped critical discussions on global population dynamics, and his work at IIASA and the Wittgenstein Centre left a lasting impact on interdisciplinary research and communication.

At IIASA, Bill played a crucial role in enhancing the Institute’s engagement with policymakers and the public. As a researcher and later as Director of Coordination and Outreach at the Wittgenstein Centre, he worked tirelessly to bridge the gap between complex scientific research and its practical implications. His ability to communicate demographic trends and their societal impacts helped shape discussions on population, sustainability, and development. His leadership and collaborative spirit strengthened IIASA’s role and fostered connections across disciplines and institutions.

Beyond his professional achievements, Bill was known for his warmth, humor, and mentorship. He formed lasting friendships across the academic and policy worlds, bringing people together with his wit, generosity, and genuine curiosity. His passion for learning and deep love for nature, family, and community enriched the lives of all who knew him.

We extend our heartfelt condolences to his family, friends, and colleagues. His legacy of intellectual curiosity will continue to inspire IIASA and the broader research community.