David Ewing Duncan is nothing if not self-aware. He knows, for instance, that his brain is shrinking. And he knows that he is among the 25 percent of humans who can't taste bitterness, although he doesn't really know why. He knows that he has enough manmade flame-retardants built up within his body to put out a small fire. Duncan also knows how much DNA he has in common with dinosaurs, and that he carries a gene that may incline him to "seek out novel situations." He knows what his doctor and his children and his medically afflicted brother think about him knowing all this stuff about himself. And now we know it, and what he... More >>>