HEATHER MCGHEE spent two years traveling across the United States talking with people about the racial divide. She found that structural racism hurts not only people of color but white Americans too. In her travels, many white people told her that they believed progress was a zero-sum game, the idea that if one group gains ground, another will automatically lose it. We’ll talk with McGhee about her new book, The Sum of Us: What Racism Costs Everyone and How We Can Prosper Together, about the zero-sum myth and the ways we can come together around issues of racial justice, economic inequality, the environment and voting rights to advance all America lives.