Does America have a ‘caste’ system? Isabel Wilkerson explains.

The word racism does not appear in “The Warmth of Other Suns: The Epic Story of America’s Great Migration,” says Isabel Wilkerson of her bestselling 2010 debut, an epic account of the 20th-century Great Migration of 6 million African Americans from the South to the North. “What they were experiencing was more comprehensive, more repressive, which is why I thought ‘caste’ was the more appropriate word.” The Pulitzer Prize-winning journalist’s riveting second book, “Caste: The Origins of Our Discontents,” builds on that insight to argue that racism alone