The countdown to the twenty-first century has begun. Almost daily some news medium reports the number of days remaining in this millennium, and the rich and famous around New York fret that the choice tables at fashionable spots have already been booked for New Year’s Eve 1999. But in a more serious vein, they will do well to celebrate the close of what historians are judging the most terrible century in terms of human misery. Hungry Ghosts, a new book by British journalist Jasper Becker, brings into focus the famine in communist China that lasted from 1959 to 1961 and may have killed as many as 30 million people. This gigantic tragedy had nothing to do with floods or drought-it was a man-made disaster directly attributable to the mad policies of Mao Zedong, and it was deliberately concealed until recently.