Throughout the world, populations are aging at an unprecedented rate. There is an urgent need to maintain the highest degree of function and quality of life for the longest period of time in older people. An understanding of aging and its relationship to disease and disability is one of the surest means to gain the knowledge needed to achieve these goals. Aging research has made significant strides in revealing the underlying processes that help determine longevity and the risk of disease. We are thus learning about factors important to maintain or improve high physical function and reduce premature death. We are developing tools to improve not only strength and balance but cognitive function, including memory, in old age. These advances are fueling health promotion and an optimism in attaining a successful old age. Efforts are intensifying to conquer Alzheimer’s disease and to prevent or delay other age-related diseases and disorders. All of us stand to gain from the prospect of a healthy, fully engaged older population: these include the rapidly growing numbers of the aged, those they care for and who care for them, and all who will join these groups in the future.