In 1924, the sociologist couple Robert and Helen Lynd arrived in a small Midwestern city they called Middletown (it was Muncie, Ind.) to study and survey the place.
Their classic 550-page "Middletown" described a community starkly split between a "working class" (factory workers and laborers totaling 71 percent of the population) and a "business class" (owners, managers and professionals comprising 29 percent). This division, the Lynds wrote, was Middletown's "outstanding cleavage" and influenced work, marriage, religion, leisure — almost everything.
The Lynds now have a provocative successor: Charles Murray of the American Enterprise Institute, whose new book — "Coming Apart: the State of White America, 1960-2010" — argues that today's class separations threaten America's very nature.