Dr. Ruth Puffer of the United States (1907-2002) was a biostatistician and public health professional. She began her career in public health as Director of Statistical Services in the Department of Public Health for the state of Tennessee. Between 1953-1970, Dr. Puffer served as Chief of the Department of Health Statistics of the Pan American Health Organization, where she was the prime mover behind the Inter-American Investigation of Childhood Mortality that PAHO. During that period she conducted two important research studies: Patterns of Urban Mortality (1967) and Patterns of Morality in Childhood (1973). Today, both studies are still considered path-breaking classics of scientific literature and have had an undeniable impact on health services throughout the hemisphere.