You know it the instant you step in the door: here is marvellous, very possibly great art, a game-changer and a joy. The works involve abstract, oftern de Kooning-esque paintings, but you don't see much of them; they're obscured by ragged tarpaulins, sheets of cheap plastic, and dress fabric. One bears a glued, crumpled terry-cloth towel. Another is occluded by an old wooden armoire, its mirrored front facing the canvas. With their draped membranes often touching the floor, the works have a mighty, sculptural presence to go with their visual ravishment. Hammons's show is somehow about everything since Abstract Expressionism - his initial inspiration before he launched his long career as a conceptualist guerrilla, surfacing now and then from jealously guarded obscurity with satirical japes, at once elegant and scorching, on themes of racial and social inequality. Now he has achieved a perfect synthesis of his political animus and his aesthetic avidity. Call it Minimalist Expressionism. Nearly every one of these works belongs in a museum, in a room of its own. Any other art juxtaposed with it would curl up and die. Through Feb. 26