“For decades, American Expressionism has been denigrated, if not ignored. Postwar conservative art critics and politicians derided the work as art by ‘Reds and fellow travelers.’ Contemporary critics are no kinder.” But Bram Dijkstra says this is grossly unfair, and he’s making a case for it in a new book on the subject. “This is not just art with a social content, it is great art with a social content.”