Can a lot more people live to one hundred and what if they did?

In the 21st century humanity will witness unprecedented, increases in the number of older people, especially centenarians, in both the developed and developing world. From a public policy standpoint, the aging of our populations and the longer lives we experience will change, the fabric of our modern world - from the funding of age entitlement programs, to the rising cost of health care, to the new ways in which we transport ourselves in increasingly more urban environments. If it becomes possible for biomedical advances to manufacture a form of biological plasticity among the new generations reaching 85 and older in the future, much like that which now exists for the recent middle-aged classes of people aged 65-85, then the future of aging will be bright. If we fail to marshal resources to confront the biological processes of aging, then it is possible that the more destructive side of senescence will emerge. In this paper, I explore the various perspectives on the future course of longevity, examine the prospects for significant increases in the number of very old people - especially centenarians - and present a general view of the demographic aging of our changing society.