A new history of art of the 20th Century suggests a new narrative, writes Eric Gibson. “Indeed, “Art Since 1900” is less a historical narrative than an extended piece of art criticism arguing for a particular point of view. In this one respect the book has something in common with Paul Johnson’s recent “Art: A New History.” The difference is that Mr. Johnson’s approach is traditional and art itself is, for him, front and center; his insights grow out of his close look at the works of art that he is writing about. In “Art Since 1900” works of art are subordinated to one theory or another, reduced to little more than illustrations. And most of the theory itself is tendentious in the extreme, pushing a political “reading” of culture that amounts to a tired paean to Karl Marx and Walter Benjamin.”