The essential point to be made about Sigmar Polke—his extraordinary and enduring relevance—has been apparent for two decades in this country and for at least ten years longer in Europe. Indeed, were it not for his singularity and long-held stance of flamboyant apartness, one might say that he has been jostling with his old friend Gerhard Richter for center-stage in the Beuysian afterglow since around 1963, when both were students at the Kunstakademie Dusseldorf, where the mythic master presided. That was the year that Polke, Richter, and Konrad Lueg (another student at the academy, who would