One of the most remarkable achievements of the 20th century has been the extraordinary increase in life expectancy, both in the U.S. and worldwide. The added years offer new possibilities for personal achievement, family relationships, work, and contributions to community, which can benefit individuals as well as society. But in order to reap these benefits of longer life, the diseases and conditions associated with advanced age, which now affect millions of older Americans, need to be addressed. This mission is ever more urgent as the population rapidly grows older. Since the NIA's founding in 1974, groundwork has been laid for today's important advances in understanding basic aging, preventing disease and disability, including Alzheimer's disease, and defining special social and behavioral issues for older individuals, their families and caregivers, and clinicians. The latest studies provide additional basic understandings as well as new interventions to treat and even prevent some of the more devastating and disabling aspects of aging. With such research continued and intensified, we can move forward in meeting the promise of extended life by improving the health and well being of older people in America.