Donald Ainslie Henderson was an American physician, educator, and epidemiologist who directed a 10-year international effort (1967–1977) that eradicated smallpox throughout the world and launched international childhood vaccination programs. From 1977 to 1990, he was Dean of the Johns Hopkins School of Public Health. Later, he played a leading role in instigating national programs for public health preparedness and response following biological attacks and national disasters via establishing the Center for Health Security. At the time of his death, he was Professor and Dean Emeritus of the Johns Hopkins Bloomberg School of Public Health, and Professor of Medicine and Public Health at the University of Pittsburgh, as well as Distinguished Scholar and former Founder of the Center for Health Security.