The Double, by Jose Saramago, trans. Margaret Jull Costa

Dogged by a doppelgänger in a hall of mirrors

The Doppelgänger has long been a recurrent theme in novels by the Portuguese Nobel prizewinner, Jose Saramago. His choice of themes has been compared with Kafka, Gogol and his compatriot, Pessoa. Saramago's hall of mirrors reflects both his own childhood, where his infant brother's death was somehow "covered" by his own continued existence, and refracts the world in which we all now live - where the cloning of a "unique" being occurs in the swirl of a Petrie dish.

The Double confronts the nightmare that, contrary to the promises of religion and science, we may after all have become multiples rather than individuals. A video replays an original film, with a character played by an actor, Daniel Santa-Clara. This character has all the transient features, from fashion sense to moustache, that the viewer - Tertuliano Maximo Afonso, a history teacher - sported five years' earlier. Tertuliano naturally wishes to reverse roles and revert to playing the lead in a life he is finding depressed and dowdy.

The closer the two identical men approach each other, the more exactly their lives not only replicate but substitute for one another. Instead of being pursued by a Doppelgänger who wishes to slay him, Tertuliano becomes subverted by one who wishes to subsume him.

Much is made of the commonality of "ordinary" people. Saramago's heroes are always ordinary: his Communist politics, if not his reading of history and his fictive imagination, dictate as much. Much too, is made of "common sense", which appears to dictate that the cock-up must ever prevail over the conspiracy theory... except when paranoia intimates that they really are out to get you.

Common sense finds that "the existence of absolute doubles" means "one of us has to be a mistake". But what if there were no mistake, what if "the really amazing thing would be that out of the six thousand million people on the planet there weren't two people exactly alike"? What if we not only found we might have a double but - the final horror - a triple or a quadruple?

Tertuliano's double, the professional actor, is here no longer the protagonist but the imitator, then the blackmailer. As each man acts more out of character, the pair converge until not even they can convincingly distinguish whose life each is leading or whose spouse each is loving. Just as actors and authors adopt pseudonyms, individuals can adopt multiple lives. So much of our existence is predicated upon other people's perceptions of who we are.

The Double is Saramago at his most practised and polished. It is philosophy and thriller rolled into one with - as ever - a tight cast of characters, including one of Saramago's own dogs. "Words are all we have," concludes Santa-Clara's wife. And, here, words are all that are required to evoke an unearthly world of counterpoint and counterfeit.

The reviewer is director of the British Centre for Literary Translation