Waste people. Rubbish. Clay-eaters. Hillbillies. Two new books, White Trash: The 400-Year Untold History of Class in America by Nancy Isenberg, a provocative, deeply researched history; and Hillbilly Elegy: A Memoir of a Family and Culture in Crisis by J.D. Vance, an affecting memoir, are well timed to help make better sense of the plight of struggling whites in the United States. Both accounts converge on an important insight: The gloomy state of affairs in the lower reaches of white America should not have caught the rest of the country as off guard as it has.