Decisive biotechnological interventions in the lottery of human life--to enhance our bodies and brains and perhaps irreversibly change our genetic makeup--have been widely rejected as unethical and undesirable, and have often met with extreme hostility. But in Enhancing Evolution , leading bioethicist John Harris dismantles objections to genetic engineering, stem-cell research, designer babies, and cloning to make a forthright, sweeping, and rigorous...