The American Economic Association and the economics profession were saddened to learn of the passing of Oliver Williamson, at age 87. A Nobel Laureate who taught for many years at UC Berkeley, Professor Williamson’s work focused on the structure of organizations. He provided a theory of why some transactions occur within firms and others occur in the marketplace. His research extended beyond economics to inform corporate decision making and how companies are structured. Professor Rich Lyons, who was dean of Berkeley’s Haas School of Business when Williamson shared the Nobel with Elinor Ostrom in 2009, said his work “permanently changed how economists view organizations.” Williamson was vice president of the AEA in 2001. For more about his life and research, read his obituaries in the New York Times and Washington Post.