Wilbur Augustus Sawyer (1879-1951) was a key figure in preventive medicine and international public health during the first part of the twentieth century. As a public health administrator, he helped expand public health departments and integrate laboratory science into public health work, both in the U.S. and abroad. During his long career with the Rockefeller Foundation's International Health Division (IHD), he served as director of the Rockefeller Foundation public health laboratory service, director of the Rockefeller Foundation Yellow Fever Laboratory (where he developed the first effective yellow fever vaccine), and director of the IHD from 1935 to 1944. Later, as Director of Health for the United Nations Relief and Rehabilitation Administration, he supervised public health work during and after World War II, and was one of the architects of the World Health Organization.