Of all the major South American novelists, Vargas Llosa may be the sunniest: he never tries too hard to hold back a sophisticated yet honest amusement at how oddly life usually moves around; his stories of 1950s Lima and Peru have a vernal lilt as well as an expected complexity. And this large new novel is both contrapuntal and positively jaunty. The (apparently autobiographical) narrator, Marie, is not yet 21, working as a newswriter for a mediocre Lima radio station--when his young, divorced aunt-by-marriage, Julia, arrives in town from Bolivia for a little amorous adventure on the rebound. . . only to find herself a wild oat sown by Marie, who puts a move on her right away. Julia, piqued by the novelty, goes along. And the flirtation turns into real romance, then into scandal, and--finally--into a brief but entertaining-for-as-long-as-it-lasts marriage. This bubbly romantic improbability is only one layer here, however--because interleaved with it are gothic yet hilarious radio soap-opera scripts written by yet another Bolivian export to Lima: Pedro Camacho, a humorless, 50-year-old, Argentine-hating troll who quickly becomes the hit of the town with his gory yet full-spirited tales of murder and obsession and ruin. (So intense and devoted is he that he even dresses up as his characters would while he writes, throwing himself utterly--and with priestly artistic purity--into his trashy but beautifully filled-out work.) Each serial, which Vargas Llosa presents as a throbbingly rococo story-summary, is more grotesque and ghastly than the next--until, at one point, Camacho, riding the crest, becomes so ornate and involved that he starts forgetting names and traits of his characters, confusing them; and eventually he has to resort to mass destruction (stadium riots, earthquakes in church) to kill everyone off and thus start clean. Two curves, then, meet in this book: the ascending, rather silly one of Marie and Julia's affair, and the grand-guignol descending one of Camacho's fall into incoherence and failure. And though the anything-but-heavyhanded Vargas Llosa doesn't stick a pin at the meeting point, you're aware of it nonetheless: storytelling is as subject to inexplicable natural laws--entropy, gravity, decomposition--as anything else. All done with the fondest savoring of the virtues of truly popular culture, innocence, imagination: a graceful, untaxing, sweetly subtle book.