HALF A CENTURY and 360 books have passed since Isaac Asimov first began to publish science fiction, and the daunting flood continues. But even a machine for writing must eventually sense the coming of night, and in recent books Asimov has consciously begun to put his vision of the world into final form. The four huge novels he has published since 1982 -- with more in the pipeline -- are determined attempts to link the Elijah Bailey robot novels of his middle career to the Foundation stories of his early years; as these series were written over a span of decades, and in their original form had nothing to do with one another, this project may seem both grandiose and foredoomed, but the rage for order scoffs at petty decorum. Similarly, there can be no other reason for the writing of Fantastic Voyage II: Destination Brain (Doubleday, $17.95) than an overpowering hunger to make retroactive sense of -- and to redeem -- one of the few creative botches of his long career.

The first Fantastic Voyage (1966), which novelizes the film of the same name and leaves intact most of the pseudo-scientific absurdities of the original, was an embarrassingly silly book for a scientist. Asimov's redemptive strategy in Destination Brain is straightforward. He simply tells the story again, but in his own words. In Fantastic Voyage, a miniaturized crew of doctors inside a wee submarine struggles through the bloodstream of a defecting Soviet scientist and cures him of a blood clot by zapping it; they then escape through a tear duct before slamming back to normal size. In Destination Brain, an American scientist, who understands the "skeptic nodes" in the brain which engender thought at a molecular level, is kidnapped by benign Russians who understand how miniaturization can be accomplished without violating quantum physics. A Russian genius lies in an irreversible coma, but may retain the secret of faster-than-light space travel in his nodes. Duly miniaturized, the crew of scientists penetrate the molecular level of Shapirov's brain, only to find echoes of their own thoughts somersaulting down his skeptic axons. Slowly the American scientist comes to realize that he has discovered telepathy.

If even this sounds pretty silly -- and it does -- an actual reading of the book gives a somewhat different impression. Like so many 19th-century tales of miniaturization, Destination Brain is in reality an educational guided tour of the human innards, and is recounted with all the elated clarity for which, as an expounder of popular science, Asimov is justly famous. If nothing much actually happens in the 100,000 words of this illuminated lecture, the text still closes with the sense of a task well done, of a gaffe redeemed, a lesson taught, another fruitful shudder of the writing machine.

A Choice of Cards

IT IS a good thing that Orson Scott Card gives interviews. In a recent one, on being asked about the simultaneous publication of Wyrms (Arbor House, $16.95) and Seventh Son (Tor, $17.95), he made it clear that the former title had languished for some time in publishers' vaults before being released, and that Seventh Son (with sequels in tow) more fully represented the current state of his art. It is good to know this. Wyrms is a humdrum quest novel with pretensions its author was clearly incapable of fulfilling, while Seventh Son begins what may be a significant recasting in fantasy terms of the tall tale of America.

At least Wyrms has more sevens. On the planet Imakulata (readers of the French comic strip Asterix the Gaul may have some idea where Card gets his weird taste in monikers), 343 generations after a human colony has been founded by a Greek Orthodox Space Captain, things have come to a pretty pass. Murderous young Patience, daughter of the deposed Heptarch and herself the rightful seventh seventh seventh Heptarch, plays Cinderella to the usurper's daughters while biding her time. When her father dies (ultimately at her hands) and the usurper orders her own assassination, she is at last given the chance to start killing people with her noose and poison darts, rather like Modesty Blaise.

Escaping the usurper's realm with her mysterious tutor Angel, she begins the long trek to Skyfoot, where Unwyrm, a classical bug-eyed monster with an ominous appendage, has been awaiting his bride since the Space Captain first gave him a taste for human folk. It is anticipated that the result of his mating with the seventh seventh seventh daughter of the Space Captain will be the birth of the Christos, who will redemptively unite in his one flesh the humans and the natives of Imakulata. The reason for this anticipation is given us neither by Card nor Unwyrm. On the road Patience picks up a brace of deposed native sibling rulers (Reck and Ruin are their deft sobriquets), a huge indomitable human male named Will, and some odds and ends. In the dizzy mayhem which concludes Wyrms, the bad perish and the good get married. Patience is rewarded with the entire world. She deserves no better.

A very simple premise fires Seventh Son, set at the end of the 18th century in an America which never experienced a revolution because Oliver Cromwell lived to a great old age consolidating his commonwealth. It is that some forms of magic actually work. Because Cromwell's heirs are the sort of Christians who find magic threatening to their rigid pieties, the American colonies have become populated, or in their view infested, with refugees from the Old World who boast various innate or acquired knacks. Young Alvin Miller, who in later volumes will be known as Alvin Maker, is the seventh son of a seventh son, and therefore comes burdened with magic potential far beyond the norm. As with Patience in Wyrms, there are even hints that he may represent a Second Coming. Future volumes, of which there will be several, may confirm this.

In Seventh Son it is clear only that in a world of seers and dowsers and torches (who read "heart-fires"), Alvin is a healer of people and things. He is a maker, and may become the Maker. Water, allied to the eroding nothingness of his primordial adversary the Unmaker, is his enemy. His childhood in the small community of Vigor Church, which is located in Wobbish Territory (i.e. Indiana), has moments of Edenic joy when he and his family seem saturated with light, as in a John Ford film. But the adversary continues to loosen the knots of the world, a Christian minister identifies him with the Devil, and political strife looms on the horizon. Alvin acquires an ally in the wandering Taleswapper, whose true name is William Blake, an impertinent suggestion on Card's part, but an effective one. Though Taleswapper quotes only a few of the simpler early poems, and though he resembles Daniel Boone to an uneasy degree, future volumes may see his portrait grow in maturity, and some of the complexity of the later Blakean vision may grace this alternate America. In the meantime, he and Alvin manage to survive the first years of the saga.

There is something deeply heart-wrenching about an America come true, even if it is only a dream, a fantasy novel. And there are dangers of chauvinism and easy nostalgia in creating an America so clearly woven by the hands of the living God. Not to speak of the dangers of creating the God Himself. But so far so good. The first volume of The Tales of Alvin Maker is sharp and clean and bracing. May its Maker grow.

A Brilliant Debut

IN The Movement of Mountains (St Martin's Press, $17.95), which is his first novel, Michael Blumlein has managed two significant accomplishments. He has written one of the best books of the year. He has also managed to be influenced by Gene Wolfe, and lived to tell his tale. The author of The Book of the New Sun, himself a very considerable parodist of earlier writers, has a knack of autonomy; his work seems self-contained, aloof, serene, and every passage seems intended down to the last detail. There would appear to be very little to extract from a Wolfe novel except devotion to craft and to the job at hand. All the same The Movement of Mountains, perhaps partly through being so much an accomplishment in its own right, is a recognizeably Wolfeian text.

Jules Ebert's story, which he tells himself as a form of confession to an unseen brother, begins at some point in the distant near future on Earth, in a cyberpunk vision of Great San Francisco here called Barea (that is, Bay Area). Dr. Ebert is one of the elite, and lives like the rest of the privileged in an armored enclave; the poor run wild in the streets, chased by mutated dogs and haunted by the first signs of an AIDS-like viral disease which seems to ravage their psyches as well as their bodies. He is a medical doctor and a victim of bulimia, governed by bouts of insatiable gorging and desperate fasts. He is very fat. He is in love with Jessica, who is attracted by fat men. In most books their relationship would be doomed by its apparent grotesqueness; it is a measure of Blumlein's stern and original mind that in The Movement of Mountains their relationship only grows deeper.

Battered by poverty and the world, Jessica contracts with the huge drug firm Mannus to do research on the planet of Eridis, where a race of biologically engineered slaves has been crafted to mine an invaluable drug. Ebert follows her. As doctor to the huge entrapped Domers, who resemble him physically, Ebert becomes politically radicalized by their plight, just as Jessica has been. Indeed, during his absence, she has been sleeping with one of them. Soon, however, she begins to show the symptoms of the viral infection, now known as Herpes Amnesiac Syndrome or HAS, and dies in a fall. Ebert dissects her, his hands dispassionate, his heart full. He discovers HAS to be less a disease than an agent of transformation. Victims share one another's thoughts; they live one another. The Domer she has slept with becomes a revolutionary thanks to this process, and Ebert assists in a successful revolt.

Back on Earth, he finds that a panicked government has declared it illegal to have been in contact with HAS without taking treatment. His response is radical, and moves the final pages of the novel into transcendental realms. In hiding, he starts to tell his story. Some Wolfeian elements are obvious -- certain tricks of narrative; the confessional form itself; the adult rightness of the love affair; the unflustered confrontation of the text with its darkest implications -- and some are less so. At the heart of both writers there is something implacable, as though nothing could budge either of them from saying exactly what they intended to say. That they both survive in a world of commercial fiction speaks well for that world, and for its readership. Michael Blumlein speaks well for us.

John Clute's latest book, a collection of essays on science fiction entitled "Strokes," will be published this fall.