This examination of the history, development, activities, successes, and limitations of the largest membership organization in the country will be of interest to anyone who belongs to or is curious about this sometimes-controversial group.

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...