Merely accruing additional years beyond the biblical span of three score and 10 would be unwelcome if they just prolonged suffering from illness and infirmity. No, we want to live better, more youthful days while we're living longer. Diet, exercise and a lucky draw from the gene pool can take us only so far, however. That's where science comes in. In this special edition from Scientific American, you'll find firsthand reports from the researchers leading the efforts to understand the mechanisms of aging. They are teasing out ways to slow the biological clock as well as the degradation that time imposes on our bodies and minds. They are battling the diseases of age, including cancer and heart disease. Medicine will continue to advance, and, we expect, society and policymakers will have to learn to adapt to the challenges of longevity--both providing it and providing for it--that await us all.