Fertility decline and urbanization arguably have been the dominant global demographic trends during the second half of the 20th century, much as rapid improvements in life expectancy characterized the earlier 1900’s. As we approach the 21st century, population aging is poised to emerge as a preeminent worldwide phenomenon. The confluence of lowered fertility and improved health and longevity has generated growing numbers and proportions of older population throughout most of the world. As education and income levels rise, increasing numbers of individuals reach “old age” with markedly different life expectancies and personal expectations than their forebears. While population aging represents, in one sense, a human success story, it also poses myriad challenges to public institutions that must adapt to a changing age structure.