'The Lacuna' by Barbara Kingsolver

Frida Kahlo, Diego Rivera, Lev Trotsky. The Mexican painter whose flamboyant art and mangled body continue to nourish a multimedia industry. The adored husband 21 years her elder, myth-making muralist and Mexican national hero. And the man on the lam whom this idealistic pair sheltered under their roof: a slight, bearded, twinkle-eyed legend, one of the troika who together dreamed up and then led to victory the Bolshevik Revolution. Trotsky was Lenin's treasured theoretician and comrade to Stalin until double-crossed by that lethal paranoiac. Hounded into exile, he became an emblem of humane communism to leftists the world over. The Great Might-Have-Been.

Given the current vogue for books that drape fictional flesh over the factual remains of Famous People, a novel starring any one of these figures would promise a solid hit. Put all three at the center of a 500-plus-page saga by Barbara Kingsolver, beloved author of "The Poisonwood Bible," and you can watch a high drive into the grandstand.

"The Lacuna" gets the inside scoop on the Fiery Threesome thanks to an entirely fictional hero whose diaries form the bulk of the novel. Harrison Shepherd is the offspring of an absent American father and a chill-hearted Mexican-born flapper on her way down the social scale rung by rung, lover by lover. Emerging self-educated and perfectly bilingual from the Dickensian ordeal of his childhood, the lad lands a job in Rivera's politically and erotically charged bohemian household. As pastry cook, typist, general confidant and taker of dictation, he's found a home.

After some lyrical but unconvincing early scenes, the first half of the novel builds to page-turning tension. Fiction based on the lives of the famous has a special kind of suspense: One recalls more or less what has to happen (a Stalinist agent will hack the revolutionary's skull with an ice ax) but not the exact timing, or the details (how the killer weaseled his way past walls and guards into the Riveras' trust), or the motivations, the hopes and fears, the devastation of those touched by the murder. That is the novelist's job.

"Lev held his hands away from his face and stared at the blood. There was so much of it. His white cuffs were soaked like bandages. It dripped onto the papers, this morning's typed drafts." After the death of father-figure Trotsky, Shepherd flees to the States, fetching up at random in Asheville, N.C. He has no real idea of what to do next.