Book excerpt: The proportion of elderly people continues to increase in the western world-nearly a quarter of the population will be over 65 years by the year 2050. Since aging is accompanied by an increase in diseases and by a deterioration in well-being, finding solutions to these social, medical and psychological problems is necessarily a major goal for society. Scientists and medical practitioners are therefore faced with the urgent task of increasing basic knowledge of the biological processes that cause aging. More resources must be put into this research in order to achieve better understanding of the cellular mechanisms that underlie the differences in life span between species and to answer the difficult questions of why some individuals age more quickly than others, and why some develop liver problems, some have heart problems, and others brain problems. The results of such a wide program of research will provide important information about the causes of many life-threatening and/ or debilitating diseases of old age; it will help find ways to prevent some of the ailments that result from aging, and it may well lead to discoveries enabling the prolongation of human life.