by Atheneum, $6.95. Ms. Prose’s new novel, situated somewhere between history and fantasy, concerns a commedia dell’arte company playing Italy and France in the late sixteenth century. On the historical side, several of the players really lived and did what the author describes—made the change from improvised performance to a written script and rehearsed action. All this makes a simple enough tale. By adding discreet supernatural trimmings, however, the author contrives to raise questions on the nature of art, style, human character, reality and illusion which give an unexpected depth to this short book.