Includes bibliographical references (pages 263-278) and index.

pt. 1. Who we all used to be. The origins of humans and the control of nature -- pt. 2. Why we sometimes need worms and whether or not you should rewild your gut. When good bodies go bad (and why) ; The pronghorn principle and what our guts flee ; The dirty realities of what to do when you are sick and missing your worms -- pt. 3. What your appendix does and how it has changed. Several things the gut knows and the brain ignores ; I need my appendix (and so do my bacteria) -- pt. 4. How we tried to tame cows (and crops) but instead they tamed us, and why it made some of us fat. When cows and grass domesticated humans ; So who cares if your ancestors sucked milk from aurochsen? -- pt. 5. How predators left us scared, pathos-ridden and covered in goosebumps. We were hunted, which is why all of us are afraid some of the time and some of us are afraid all of the time ; From flight to fight ; Vermeij's law of evolutionary consequences and how snakes made the world ; Choosing who lives -- pt. 6. The pathogens that left us hairless and xenophobic. How lice and ticks (and their pathogens) made us naked and gave us skin cancer ; How the pathogens that made us naked also made us xenophobic, collectivist, and disgusted -- pt. 7. The future of human nature. The reluctant revolutionary of hope.

1190L Lexile