A. ATTANASIO is a relatively new writer whose short fiction has been published in markets as diverse as the orthodox sf anthologies New Dimensions and Epoch, and the collection of eldritch H. P. Lovecraftiana, New Tales of the Cthulhu Mythos. Radix (Morrow, $8.95) is his first novel.

It's a hefty beast -- some 446 pages in tradepaper format, along with an additional 20 pages of appendices. The packaging and promotion fairly scream "instant classic," ranging from the snazzy Fred Marcellino cover to the obvious and frequent comparisons with Frank Herbert's Dune to the sheer bulk. Thick books are very marketable these days.

Even the title seems calculated for effect. Radix is a nice, punchy, trendy, single-word label with which to conjure. What's it mean? The appended vocabulary explains: "Radix: a mantic term for the root of existence, the void, or, if you prefer, the isostasis in which the infinite-dimensional space of the multiverse is imbedded; within this void, everything exists; the kro called it wu, ain soth, and sunyata." Got that? Feel free to use the text above as an accurate first impression of most of the novel.

Radix opens on a radiation-based Earth, some 13 centuries from now, in a scene comfortingly like contemporary Peoria. In a grubby, tacky industrial town, fat, sloppy, hulking Sumner Kagan hunts and kills thugs as a sort of hobby. Sumner is a callow youth with one marketable characteristic -- he possesses a "white card," attesting that he is one of the few genetically normal human beings left after the Earth was bathed for more than a millennium in arcane cosmic energies following our magnetic field's destruction by the Line, an energy beam generated from a massive black hole at our galaxy's core.

The Earth is an alien landscape of mutations and transmuted realities, fraught with the conflicting plans of various cultural/-political/biological factions. The Masseboth is the society of "normal" humanity, essentially trying to keep the status quo. Its power base derives from the eo, the computer-stored memories of the mantics, the intelligence-boosted humans from our own relatively near future. Then there are the voors, human-body-possessing telepaths who are refugees from Unchala, their home-world closer to the galactic core. The Masseboth try to exterminate the voors. The Masseboth are also not too keen on the distorts, the human mutants. Then there are the yawps, genetically engineered simianhumans.

Behind all the power-jockeying is the Delph, a virtually immortal entity evolved from Jac Halevy-Cohen, one-time Israeli fighter pilot and biologically-advanced Van Vogtian superman. The Delph is aided by Rubeus, a powerful Artificial Intelligence.

All this, of course, is merely stage-dressing.

What the novel itself is about is a traditional science fiction theme: superman, the god/man figure, transcendence of existing reality. Radix traces Sumner Kagan's odyssey from flabby punk to head honcho of a (potentially) reborn Earth. The novel does this through an exhaustive and kaleidoscopic series of adventures in classical quest format.

For the first half or so, Radix is exciting, challenging, fascinating. Attanasio writes with color and invention. Then the thickets both of verbiage and philosophy begin to close in. All manner of mysticism starts to lurch in from the wings. The novel rapidly escalates to being Significant. There's nothing wrong with that, I suppose. I admire the ambition.

Unfortunately Attanasio's synthesis of Eastern religion and Western science becomes obscured by increasingly dense prose. Lucid images at the beginning evolve to mud. To be fair, the author attempts to undercut pomposity with humor; but those attempts are too few. And too late.

Sumner Kagan eventually carries out his destiny as eth, the Delph's incarnated fear-doppelganger. Rubeus crashes to doom in an Armageddon of esoteric energies. And we, the readers, are enveloped, finally, in a nova of adjectives and tortured nouns.

I think the word I'm looking for, the one thing A. A. Attanasio needs most, is control. On the basis of Radix, though I'm ultimately disappointed in the murky fusion of mysticism and muons, I look forward to the author's next work.

Meantime, what with promotion, packaging, and vocabulary, I'll wager that Radix will sell on college campuses like crazy. An instant classic, indeed.

Hilbert Schenck is, I think, a greatly underrated writer. His short fiction, generally centering around oceanographic concerns, has been appearing for several years in the Magazine of Fantasy & Science Fiction. Last year Pocket Books published a collection of his stories called Wave Rider. Now his first novel has appeared. It's called At the Eye of the Ocean (Pocket/Timescape, $2.50) and it is very good indeed.

I'm not sure how to categorize this novel. At the Eye of the Ocean could be called fantasy (it deals with psychic survival after death). It could be termed science fiction (a central concern is the total -- including telepathic -- ecological relationship between humanity and nature). This probably justifies the term science fantasy.

Schenck presents us with an alien world -- not a distant planet or a far future, but our own Earth . . . New England in the mid-19th century. His evocation of a harsh Cape Cod existence, of sailing life, of the thoughts and feelings of the women and men who actively opposed slavery, all seem convincing enough. All provide a vivid backdrop for portraits of warm, identifiable, fleshed-out characters with remarkable talents.

The reader first meets Abel Roon as a young boy orphaned by tragedy in 1841. Able has a talent, a gift -- he has a peculiar empathy for the sea. With his mind, he can tap into the complex, almost sentient system of tides, currents and creatures that composes the ocean.

As with Radix, At the Eye of the Ocean traces the evolution of a higher consciousness embodied in a man. Like Sumner Kagan, Abel Roon is a potential superman. But unlike A. A. Attanasio, Hilbert Schenck exercises a firm control over his materials and his character. The key is low, but certainly no less convincing for its lack of pyrotechnics.

After his parents' death, Abel is taken in by Judge Folger, a crusty old abolitionist. The boy -- in the process of becoming a man -- soon is actively involved in helping run escaped slaves north to freedom. No overly romantic adventure, this. The freedom business is hard and dirty, and when Abel kills in cold blood to preserve the secrecy of the enterprise, he feels it in his gut. As do we. The armed conflict between slavers and abolitionists, we get the impression, was more romantic an adventure than Vietnam.

This is the sort of tone I find refreshing in something marketed as middle-of-the-road sf.

Early on, Abel meets Hope Mayhew, the judge's granddaughter. The course of their growing love is a main thread of the novel. The other thread is Abel's thirst for knowledge about his talent, the desire to seek out the eye of the ocean, and "a place wisdom. . . where the ocean and man can speak . . . together."

The culmination of Abel's quest is a statement about human's truly integrated place in a complex and balanced natural universe. The final dash of mysticism is not objectionable. The novel arises down to a scene of affirmation evoking the conclusion to D. M. Thomas' The White Hotel. I'm not attempting to compare the two -- just to indicate, from interest, that first-rate literary minds may run parallel.

Positive, but not mawkish. That's also refreshing.

My recommendation of At the Eye of the Ocean is not without some qualification. Schenck does take some literary risks and these don't always work perfectly. That the story's point of view rotates from Abel to Hope to Hope's mother, father, and son isn't innately a problem. But it does seem that Hope's narrative, a substantial portion of the novel, is (and perhaps necessarily so) too synoptic.Hope tells us much more than she shows us. There are other quibblesome flaws, but certainly none fatal.

The book deserves to be read.

Ben Bova's Voyagers (Doubleday, $14.95) gets started very slowly but then picks up in exemplary fashion.

Doubleday has elected to publish Voyagers as a non-category novel rather than an entry in their sf specialty line, and I wish them well. The title, the cover (painting of Jupiter on a black field), the thickness (391 pages), and the subject matter all seem orchestrated to hit the market at just the right time. The theme is the long- and well-used one of first contact between human beings and extraterrestrials. Ben Bova should know his material -- he's authored 45 books, both fiction and nonfiction, been a marketing director for a prominent R&D lab, and is presently editor of Omni magazine.

I had the feeling, reading Voyagers, that there was some auctorial intent to aim this novel at the general, non-sf audience. I'm afraid that much of the material will appear tired and over-used to the reader familiar with similar stories.

The novel centers around the discovery that an object, probably an alien starship, is heading from the vicinity of Jupiter toward Earth. Astrophysicist and one-time astronaut Keith Stoner knows it's of paramount importance that the human species do something about this -- recognize and accept the existence of extraterrestrial intelligence, and mount a manned expedition to intercept the interstellar vehicle.

At first the authorities keep the revelation a secret. Stoner finds himself whisked away by Naval Intelligence. Meantime, both the American and Soviet governments start gearing up plans to capitalize politically, militarily and technologically on whatever goodies the alien phenomenon may provide.

In true best-seller style, the book introduces a broad cast of stock characters: The tough, party-line, female KGB agent; the tired English double-agent she controls with tiny electrodes planted in his brain; the gay Nobel-laureate cosmologist who is recalled from monastic retreat by the Vatican to check out Catholic interests in the man-is-not-alone-anymore affair; the unstable Dutch astronomer zonked out on PCP; the randy Russian language expert who puts personal friendship and the spirit of scientific inquiry above national interests; the lucky female grad student who is the middle-aged, middle-class male's interpretation of a liberated woman, and so forth.

Most of the book is taken up with the mechanics of first coping with the idea of ET contact, then getting ready for a combined Soviet-American space mission, finally sending Keith Stoner and a Russian cosmonaut to check out the alien spacecraft. It's neither good nor bad -- just standard stuff. Competent is probably the word I should use here. Despite desultory pokes at making the characters fully-dimensional people, the focus remains on the uncomplicated, linear plot.

Excitement finally comes after the exploratory probe launch when Stoner and his partner reach the intruder. This is where the oft-cited sense of wonder in science fiction comes into play. Ben Bova felt wonder when he visualized that spaceship. He could empathize with Keith Stoner when the scientist jet-packed across the void between Earth ship and ET. As readers, we feel wonder too, the awe at making contact with something from beyond.

And when Stoner ingeniously devises a sacrifice by which he will force humankind not to ignore the long-term ramifications of the alien ship -- that's affecting. And that's what contemporary science is all about.