A young fabulist's highly touted first novel (``already sold in seven countries'') combines the techniques of Thomas McGuane with bits of Lolita and The Picture of Dorian Gray. Lonely, nondescript Jeremy is a fact-checker for Screen magazine when, during lunch hour one day, a lovely young woman who calls herself Lady Henrietta (after Wilde's Lord Henry) asks whether he'll come to her apartment to pose nude for a painting. (She ordinarily paints beautiful male nudes by commission from Playgirl.) Jeremy poses twice, and only then learns from Lady Henrietta's voluptuous, mischievous, lively, and precocious 11- year-old daughter Sara what his virtue as a model is: Henrietta considers him an extreme example of an Optical Illusion--meaning ``almost but not quite something.'' In Jeremy's case, he's ``almost ugly, but not quite, almost good-looking, but not quite. You almost look like you might commit suicide at any second, but not quite.'' Nonetheless, oddly nubile Sara falls in love with him, and having enlisted her mother's help seduces him (in some detail) on a rip- roaring trip to Disneyland. For the first time in his life Jeremy develops a passion--for preadolescent Sara; but Sara has developed a deadly brain tumor. Before it can kill her, however, she's run over by a car driven by a woman who's swerved at the sight of a nude man--Jeremy's only friend Tommy, as it turns out--standing in a window above the street, staring at a bird. With Sara dead, Henrietta, grieving, insists on painting another portrait of Jeremy--except that in this one he looks just like Sara. And, indeed, he has come to resemble Sara--to be mischievous, lively, and much more voluptuous than he was at the beginning of the novel. The ending is ambiguous: as in Wilde's novel, ``there was hope.'' Sara and Jeremy's mother are splendid, but the book's surreal elements are only intermittently successful and its shape and theme are wobbly. Still, an interesting debut.