Louise Nevelson, one of the most important American sculptors of the twentieth century, was a beautiful woman who lived so audacious a life that by the time of her death she was a legend both inside and outside the art world.   Born Leah Berliawsky in Czarist Russia in 1899, she grew up in Maine, ostracized as a Jew and a foreigner. At twenty she escaped to Manhattan as Mrs. Charles Nevelson, eventually leaving her husband for a life devoted to art....