AN INSTANT NEW YORK TIMES BESTSELLER The "lively" (The New Yorker), "convincing" (Forbes), and "riveting pick-me-up we all need right now" (People) that proves humanity thrives in a crisis and that our innate kindness and cooperation have been the greatest factors in our long-term success as a species. If there is one belief that has united the left and the right, psychologists and philosophers, ancient...