By Gene Wolfe

Tor. 372 pp. $17.95

GENE WOLFE'S career has thus far been dedicated to making us see in a new light some of what we had thought of as the stock habits of science fiction and fantasy; in The Urth of the New Sun, he does this again, not least in the way in which he forces us to consider the possibilities and implications presented by sequels. In the four volumes of the Book of the New Sun, he showed a dying future Earth torn by wars between human nations, wars manipulated by vast sea beings and by alien visitors from another universe; he showed us the progress of the torturer Severian from a frightened boy crouching in a desecrated graveyard to his accession as Autarch, nominal ruler of the planet and the one capable of pleading for its survival.

The sequel shows us nothing of his rule, or of his love for the shadowy Valeria, but starts with the action for which he achieved the throne. He is aboard a ship, sailing through time and space, from old and fallen worlds to a new and heavenly universe, to be judged and perhaps to redeem Urth, to rekindle its sun. To the crew, accustomed to saviors, he is just another passenger, one who finds himself beleaguered by strange beasts, assassins and mutineers, wandering eternal treacherous corridors without proof of his significance. Yet he stands his trials and emerges victorious, to find victory not a single act.

Zigzagging through the ages hinted at in the earlier volumes, he humiliates the two-headed universal tyrant Typhon, leaving as relic the magic thorn he is so often to use; he witnesses the acting-out in real life of the climax of Dr. Talos' play, in which he had earlier been merely an actor; he travels still further back to become the dome-building demigod Apu-Punchai, whose abortive resurrection he once witnessed; finally he achieves his destiny as fisher-king of a healed Urth. For those who wish to read of giant spaceships and time paradoxes, there is plenty here, God's plenty.

So too for those who wish to read deeper. The vast spaceship through which Severian hunts and is hunted is at once the stock Big Dumb Object of space opera, meant to awe us with eclipse-causing bulk, and those corridors and bastions through which Kafka's cognates pursue their just ends. The island of Urth's judgment, the shores of the brook Madregot, which runs through universes and times, are described with a paradisical simplicity which owes much alike to Dante and to later Christian fantasists like C.S. Lewis. The judgment of Urth rests in the hands of beings more like the seraphs of Cabbala than conventional sf aliens. Severian becomes several kinds of godling, and, buffeted by imperial soldiers and betrayed by his most loved disciple, more than one kind of redeemer.

MUCH WE had guessed is here justified. This volume makes of the whole work a palimpsest, in which moments from an underlay of earlier versions of reality crop up suddenly, producing seeming inconsistencies such as the moments here when Severian, like Schrodinger's cat, is both dead and alive. Borges' maze-tale "The Garden of Forking Paths" is imitated and surpassed, since Wolfe's use of time paradox makes more plausible that events appear in different recensions. Material that in earlier volumes stayed misty -- the identity of Apu-Punchai, the source of the Conciliator's claw -- are here amplified and made to fit. The process of redemption is also one of reconciliation, not least of the reconciliation of texts.

To have a second thought, to go back and do it over, is not to acknowledge any serious mistake. A work by a believer -- Wolfe is a practicing Catholic -- which has as its central act the intervention of the divine in history is bound to reflect complexly on artist as creator and Creator as artist. Some schoolmen held that a fallen and redeemed universe was one more elegantly, interestingly perfect than an unfallen one could have been: The Urth of the New Sun makes of the whole sequence a more perfect work by showing us inconsistencies before ironing them out. At the end of the book, Urth is washed clean of flaws and of most of its inhabitants. But not least of the encounters of doppelgangers that recur throughout these texts is the clash between the proliferation of the ornate, and the implied boast about the creation of secondary universes, and the pious humility with which the book closes.

The title of Talos' play is Eschatology and Genesis; Talos, thricely created as the homunculus of a character in a believer's novel, essays a drama of wild intrigue and redemption, an imperfect reflection within The Book of the New Sun of that text and of its coda, a quasi-burlesque whose lines are echoed by Severian at his mission's climax. Severian says of the play that it was "a great tale that had being only in {Talos'} mind . . . could only be expressed in the ringing of bells and the thunder of explosions, and sometimes by the postures of ritual." Yet, if never fully understood by audiences, it awakened much emotion in the darkness. Wolfe's more perfect tale of the understanding of the divine and the birth of a new world has its obscurities, forces us to read and reread if we are to hope fully to take its meaning, yet in the end its importance lies in the complex of excitements and emotions that it awakens.

Roz Kaveney reviews regularly for The Times Literary Supplement, The New Statesman, and The Literary Review.