They distill more than 20 years of research and first-hand accounts from the most biodiverse ecosystems on Earth into straightforward principles and guidance for confronting our culture of hyper-novelty.For evolutionary biologists Heather Heying and Bret Weinstein, the cause of our woes is clear: the modern world is out of sync with our ancient brains and bodies. We evolved to live in clans, but today most people don't even know their neighbors' names. Differences between the sexes once served a necessary evolutionary purpose, but today many dismiss the concept of biological sex as offensive. The cognitive dissonance spawned by trying to live in a society we're not built for is killing us.

    Charting the most cutting-edge scientific breakthroughs, and marshalling his decades of research and clinical practice, Walker explains how we can harness sleep to improve learning, mood and energy levels, regulate hormones, prevent cancer, Alzheimer's and diabetes, slow the effects of aging, and increase longevity. He also provides actionable steps towards getting a better night's sleep every night.