by Muriel Spark. Knopf. $4.95. The destructive im pulse has been incarnated by Miss Spark in the person of a nondescript British spinster, named Lise and of no particular age. Outrageously dressed, childishly rude, Lise takes a trip to Italy, spreading disaster and dismay wherever she appears. It is her hobby and her pleasure to create misery—or so one infers, for although the reader is informed in detail of what Lise does, what she thinks is never revealed. She is Iago with all the soliloquies cut, which makes for constantly surprising and intriguing action, but leaves each reader free to invent motives for that action. Since the novel is not intended as realism, Lise can be viewed grandly as Satan at large in unlikely disguise, or more prosaically as the acting out of female paranoid daydreams, with several teasing possibilities between these two points. However Lise is explained, her adventures form a brilliant backhanded cliff-hanger.