For more than fifty years, we have been waging, but not winning, the war on cancer. We’re better than ever at treating the disease, yet cancer still claims the lives of one in five men and one in six women in the US. The astonishing news is that up to two-thirds of all cancer cases are linked to preventable environmental causes. If we can stop cancer before it begins, why don’t we? That was the question that motivated Kristina Marusic’s revelatory inquiry into cancer prevention. In searching for answers, she met remarkable doctors, scientists, and advocates who are upending our...