Aging in the 21st century is a story of success, but it is also a story with subplots of concern and peril. One of the best tools people can use when facing concerns and perils is information. Information about aging abounds. Much is known, for example, about how lifestyle and societal practices influence how long and how well people live. But the question of what actually causes people to age is but one of many "Age-Old Questions About Aging" that remain unanswered.

Much is known about "How the Body Ages"—that is, the changes that can occur with aging itself, apart from the influence of disorders and other factors.

In many countries of the world, more and more people are living longer. "The Aging of America" sheds some light on how the growing group of older people looks from the perspective of a whole nation or society: who is old, what resources they have, where they live, and how healthy they are.