1926. Gas is 17 a gallon. Haircuts are 25 cents. And U.S. Route 66--two thousand miles of road and concrete--connects Chicago with Los Angeles, making long-distance travel a reality for millions of Americans.

Often called America's Main Street, this famous highway played a key role in the development of U.S. industry and commerce. It offered the prospect of a better life in the West for families trapped in rural poverty along its path. And, by the early 1940s, it was a lifeline in the U.S. war effort. Route 66 quickly became part of the American Dream, generating its own myths and...