The thing about preaching...is that persuasion is not its principal aim. Often, the goal is to send churchgoers back into the world renewed, perhaps edified but surely fortified for the trials that await. This is what one gets from McGhee’s stunning, sobering, oddly hopeful book, The Sum of Us: What Racism Costs Everyone and How We Can Prosper Together. She is not fishing for converts in a depleted sea. She is encouraging the faithful and equipping them for the kind of intellectual and spiritual journey that produced her book.