Clement Greenberg (1909-1994), champion of abstract expressionism and modernism--of Pollock, Mir , and Matisse--has been esteemed by many as the greatest art critic of the second half of the twentieth century, and possibly the greatest art critic of all time. On radio and in print, Greenberg was the voice of "the new American painting," and a central figure in the postwar cultural history of the United States. Greenberg first established his reputation...