The processes that control senescence have been the subject of more then a century of serious biological research. Two institutions closely involved in this programme, the Society for the Study of Human Biology and the British Society for Research in Ageing, held a joint symposium in 1984 to consider human ageing and longevity from an interdisciplinary point of view. The resulting book has four main sections: the evolution and genetics of ageing, biological age assessment, demographic and social aspects, and the nutritional and physiological aspects of ageing and longevity. The fundamental nature of the subject will generate interest across a wide range of biological and medical disciplines.