by Atheneum, $17.95. When some long-forgotten critic announced, “The three-volume novel is extinct,” Rudyard Kipling responded that, although it “cost a watch to steer her, and a week to shorten sail,” the old three-decker was the “only certain packet for the Islands of the Blest.” The three-volume novel (alias the threedecker) remains officially extinct, but Mr. Jennings can write the equivalent, carrying the reader to shores of wonder and trails of wild adventure in one exuberant volume. He has done it in this tale of the matters that Marco Polo discreetly omitted from his official account of his travels in Kithai. One character observes that Polo can be easily recognized by his “proximity to the nearest available trouble,” but it is a kindly understatement. By his own first-person admission, Polo is inquisitive, meddlesome, and a woman-chaser. Readers who dislike erotic romps, or explicit tortures, or disrespectful comments on any and all religions, will find him objectionable company. The unregenerate will find him an endlessly intriguing guide through constantly surprising events..