Among architects and preservationists, the writings of Viollet-le-Duc (1814-1879) have long been considered major resources. They inspired a generation of American architects, including Frank Furness, John Wellborn Root, Louis Sullivan, and Frank Lloyd Wright. In 1894, the critic Montgomery Schuyler observed that Viollet-le-Duc's books "have had the strongest influence on this generation of readers." But for the past century, all but one of his works...