The far-reaching effects of the ageing of populations is being increasingly appreciated. Lengthening longevity, associated with decreasing family size, evokes rising charges, socioeconomically, and on health services. Information on these and other parameters is presented for developed and developing populations. Examples are given, with lessons to be learned, of long-living segments of populations, past and present. The roles of diet, physical activity, and smoking and alcohol consumption also of attitudes, are discussed. It is concluded that if the middle-aged and elderly could be persuaded to follow long-term practices associated with good public health, then morbidity could be compressed, and disability-free years extended. However, this goal could only be achieved with a high level of motivation.