Chip Walter is an author, journalist, filmmaker, and former CNN bureau chief. He has published articles in National Geographic, The Economist, the Wall Street Journal, and Scientific American, and he has written four earlier books, most recently Last Ape Standing: The Seven-Million-Year Story of How and Why We Survived. He lives in Pittsburgh. You can learn more about him and his writing at www.chipwalter.com and on Facebook or Twitter @chipwalter.