On the enormous loom of "Gemini," Tournier weaves banalities into wonders: rubbish dumps, a tapeworm, Venetian honeymoons, even the weather are here transmuted into the stuff of marvels.

"Gemini" is about a pair of identical twins, collectively known as Jean-Paul. Saying this, however, is a bit like saying that "Ulysses" is about a man walking around Dublin, because Tournier uses the theme of twinship to explore a near infinity of dualities. In addition to playing with such traditional oppositions as heterosexuality and homosexuality, city and countryside, heaven and hell, Tournier elaborates ingeniously on the profound opposition of chronology and meteorology—the fixed, regulated march of the hours on the one hand and the wild, unpredictable fluctuation of the seasons on the other. And, in a passage of startling metaphysical originality, one of the characters says that "Christ has to be superseded"—not, in Manichaean terms, by Satan, but...