AARP is one of Washington's most influential interest groups, but just who does it represent? To some, it represents the narrow, special interests of older Americans who already consume more than their share of government benefits. To others, its advocacy encompasses everyone, including those with elderly parents and grandparents--and those who will comprise the older generations of the future.

The most comprehensive volume ever written about AARP, the book begins with a chapter on the organization's history, going back to its founding in 1958 and its roots in the National...