Human longevity is drastically increasing. In the coming years, it seems possible that we will live out our extra years or even decades in vitality and good health. But will we be able to keep pace? In an age of rapid technological and scientific progress, our communities, politics, and economic institutions are underprepared for the coming challenge of longer human lives. If the average lifespan extends to 100 or even 150, what will it mean for marriage, the work force, and personal financial planning? What about the economy and entitlement programs?