Eleanor Josephine Macdonald (born 1906) has been a pioneer in the field of cancer epidemiology. Over the course of forty years, she made several significant contributions to the understanding of cancer and was a strong advocate for early treatment of cancer symptoms.

Macdonald was the first cancer epidemiologist; previously, epidemiologists had only researched communicable diseases. While working at the Massachusetts Department of Public Health, she was the first to precisely determine incidence rates for cancer. In Connecticut, Macdonald developed the first population-based cancer registry. Later, she proved that there is a connection between sunlight and malignant melanoma of the skin. Many of the cancer programs in existence today are due to her efforts, or are patterned after programs she developed.

Macdonald, the third of six children, was born on March 4, 1906, in West Somerville, Massachusetts, to Angus Alexander, an engineer of Scottish descent who worked for the American Telephone and...