The American public has not given works by Barbizon artists star billing in a little over a century. Where once Americans were proud of themselves for having recognized Millet’s talents early, they are now harder to please. Since Impressionist art has risen to blockbuster fame, it takes a monumental effort to call attention to the considerable but subtle charm of what Millet referred to as “rustic art.” The subtitle of this exhibition, “Drawn into the...