The applications of Part Two are relatively straightforward guides to better aging. The topics of Part Three are more complicated. Much of what we hear about longevity, quality of life, and cognitive enhancement should be confronted with skepticism. But there are many bright spots. No, we can’t live forever, but we can live longer than ever before. We can stay active well into our nineties and beyond and make valuable contributions to our world. And, no, playing computer games won’t save you from Alzheimer’s, but . . . Read on, wise reader.