The "king's best highway," later known fondly as the Post Road and eventually as U.S. Routes 1 and 20, began as a series of Indian paths wending their way from Boston to New York City. Eric Jaffe, an agreeable guide, travels this multibranched highway through four centuries to provide an episodic history of roads and their ramifications.

The early wilderness paths, he tells us, were often no more than 18 inches wide—one thinks of Nathaniel Hawthorne's Young Goodman Brown setting out to meet the devil in a darkling forest...