Roland Barthes, whose centenary falls in 2015, was a restless, protean thinker. A constant innovator, often as a daring smuggler of ideas from one discipline to another, he first gained an audience with his pithy essays on mass culture and then went on to produce some of the most suggestive and stimulating cultural criticism of the late twentieth century, including "Empire of Signs," " The Pleasure of the Text," and" Camera Lucida." In 1976, this one time structuralist outsider was elected to a chair at France s preeminent College de France, where he chose to style himself as professor of...