Dr Armstrong is a public health scientist who has used quantitative methods in his scientific contributions to epidemiology, especially in the field of cancer epidemiology. He has advanced our knowledge of the epidemiology, aetiology and control of malignant melanoma of the skin, studied the role of diet in human carcinogenesis in relation to cancers of the breast and endometrium, and considered the epidemiology and control of asbestos-related cancer. He has also clarified the relationship of diet and alcohol to blood pressure, and analyzed technical aspects of exposure measurement in epidemiological research. Dr Armstrong is arguably the most outstanding public health scientist in the history of Australian epidemiology.