Despite an enormous investment of effort throughout the world, cancer is still a major barrier to human longevity. Cancer deaths are estimated to be more than five million globally. Currently responsible for about 20% of all deaths in developed coun­ tries, the burden of cancer is steadily increasing in the developing world, following the control of malnutrition and infectious and parasitic diseases. Deeply impressed by the report of the Symposium on Geographic Pathology and Demography of Cancer held at Oxford in 1950, and through his preliminary work on cancer mortality statistics in Japan, Professor M. Segi decided to devote his life to the fight against cancer by establishing worldwide comparative cancer statistics-one of the landmarks in cancer studies and in cancer prevention strategies. He and his associates published six volumes of Cancer Mortality in 24 Countries with reliable mortality statistics covering 1950-1967, using the world population which he had derived as a standard. These publications rapidly became standard works of reference on the subject throughout the world. Professor Segi was a pioneer of cancer epidemiology in Japan. He cleaved a path through the jungle of cancer using epidemiological methods. By promoting cancer studies, he overcame the poor understanding of malignant disease which existed after World War II, when cancer mortality rates were still low.