ONE OF the oldest arguments around is whether the division of fiction into genres is helpful or not. Sometimes it seems valid enough, Hal Clement and E.R. Eddison hardly belong in the same room, much less on the same shelf. Consider, however, the case of Orson Scott Card, who writes horror, fantasy and science fiction, as well as stories that might be any or all of the above.

Maps in a Mirror (Tor, $19.95) collects all of Card's short fiction except for those stories already gathered into his Alvin Maker story-cycle and his theme collection The Folk of the Fringe, and one story he wishes (as is his right) forgotten forever. The collection is broken into five "books" interspersed with generous amounts of autobiographical material and an explanatory afterword for each story. It fairly cries out for us to judge the man and his career.

Which would be wrong. Of 45 stories, some 34 were written in one furious burst of productivity and published in 1977-81 (13 in 1979 alone!) and five appeared last year. In between, Card's concerns have changed, shifting from myths of retribution to myths of redemption. What we have here is a record of an unhappy period of his life, leavened by more recent material.

But it is powerful stuff. Card writes a plain, stripped-down prose, almost devoid of physical description or literary embellishment. His stories are lean prose engines that go straight for the emotional jugular. The "Tales of Dread" in his first book are horror stories that implicate the readers in the sins of the protagonist, and explore the soul's yearning for punishment. In "Eumenides in the Fourth Floor Lavatory" a man is haunted by babies with suction-cupped flippers. In "Closing the Timelid" a hedonist finds death "everything God promised the righteous and Satan promised the sinners rolled into one." In "Freeway Games" a speeding driver yearns for a woman who will torture and kill him. Only in "Lost Boys" does Card hold out the possibility of forgiveness and reconciliation -- a possibility immediately torn to shreds in a metafictional postscript. I would not recommend anybody read these straight through.

The "Tales of Human Futures" demonstrate, if anything, that Card is more interested in the fiction than the science of sf. But his "Fables and Fantasies" cut closer to the heart. "Unaccompanied Sonata" is in fact close to being the archetypal Card story, with the innocent and superior protagonist -- here an almost impossibly talented composer -- who undergoes savage persecution by an unjust and arbitrary authority, and after a lifetime of suffering wins a purely moral victory. It's an emotional button-pusher by a man who knows how to push buttons, and a template to which he returns again and again, in such stories as "The Bully and the Beast" and its dark obverse, "Sandmagic."

The fourth book, "Tales of Death, Hope and Holiness" includes Card's specifically religious works, those concerned with the violent collision of man and a cruel universe. In "Kingsmeat," arms, legs and breasts are amputated and harvested to feed alien overlords. The pilgrims in "Holy" one by one die, in their quest to carry a bag of feces to a mountaintop. The hero of "Eye for Eye" is cursed with the involuntary power to kill whoever makes him lose his temper. The only quiet story here is "Mortal Gods" in which immortal aliens worship human beings because of all races in the universe only we die. Again, I would not recommend anyone read these stories straight through.

A final section contains obscure material, stories that have been rewritten as novels, moral fictions from Mormon magazines, and the like, for the archivist and amateur scholar in us all. It is intended as a bonus for those who buy this edition, and will not be included in the two-volume paperback reprint. Orson Scott Card fans will want to spring for the hardcover. Heedless of Their Fate GEOFF RYMAN'S newest novel is science fiction to the bone. The Child Garden (St. Martin's, $19.95) is set in the aftermath of the biological revolution, in an age when infants are educated by viruses, personality is contageous and opinions can be caught like a summer cold. Ryman's future is cunningly worked out, and some of his inventions are good enough to make a biologist laugh with delight.

To introduce the reader to this dauntingly complicated milieu, Ryman makes a canny choice of protagonist in Milena, who is comic, touching and engaging all at once. Milena first appears in gloves and parasol, boiling her forks and spoons and flinching from sneezes in abject terror. She is far more intimidated by her postelectronic culture than are we. By the time she has grown into an influential and assured personage, we have been ushered into an easy understanding of her world.

It is a world she is right to fear. Due to ancient mistakes, human lifespan has been cut in half, and people die in their early thirties. To keep such mayfly lives going, childhood has been all but eliminated. After an all-too-brief stay in the Child Gardens to be infected with knowledge and skills, the undersized adults are put to work.

Ryman's people are complex, comprehensible and enormously good company. Rolfa, the bearlike, genetically engineered composer, is a fine creation, but only slightly more so than such lesser characters as the Snide, the postperson Joseph and Bob the Angel. Ryman's future London is Asiatic in its complexity, poverty and cultural variety.

The plot mixes together a tragic love, a campaign to stage an operatic version of "The Divine Comedy," and the nearing end of the age of humanity. As events unfold, we find that what seemed poverty is hidden wealth, and that tolerance masks oppression. Mankind is in an interim learning stage, a Child Garden of the species.

Unfortunately, The Child Garden falls prey to one seriously happy ending. By the time Ryman is done loading Milena down with rewards for good behavior, she can barely stagger off into the sunset, so burdened is she with immortality, true love and eternal happiness. It's satisfying enough, but nowhere near so profound as promised by the brilliance of the opening chapters.

Flawed as it is, though, The Child Garden is hands-down one of the best science fiction novels of the year. Geoff Ryman is a powerful and original writer, one of a handful who are moving science fiction into a new decade and, beyond, a new millennium. Consider this novel a step in the right direction. The Horror, the Horror MIDWAY through Thomas Ligotti's Stories of a Dead Dreamer (Caroll & Graf, $17.95) is a story that comes close to summarizing his art. A hypnotist with impossible, "labyrinthine" eyes entertains a houseful of partygoers with illusions of surpassing beauty and strangeness. All they want, he knows, are cheap tricks, patently fraudulent death and make-believe pain. Determined to enlighten them, the hypnotist sets the revelers to dancing and flirting with his seemingly beauteous assistant, a woman only he can see is actually a resurrected and rotting corpse. The story ends at the instant he breaks the illusion and the unity of the dreadful and the sublime stands revealed.

Stories of a Dead Dreamer is full of such inexplicable and alarming delights. Nothing is rationalized. More often than not the horrors are only suggested. Everything is subordinate to the main task of evoking a wondering sense of supernatural dread. It is as if each individual work were but one facet of a single darkly transcendent vision of the world.

Rubbed free of the specifics of time and place, Ligotti's creations seem to float within their own private universe. The feel and language of "Masquerade of a Dead Sword," in which a Renaissance bravo is persecuted by the dark soul of the world, are not greatly different from those of "Dr. Locian's Asylum," wherein a town must live with the legacy of authority abused. Even when Ligotti takes on the gleefully mad persons of "The Chymist," the voice is unmistakably and uniquely his own.

The unique, occasionally purple prose carries a heavy load of artifice -- narrative frames, stories within stories, diary entries and quotes from imaginary works. At one point in "Eye of the Lynx" experience is rendered as pages in a nonexistent book. Given this self-conscious focus, it is no surprise that several works have a writer for protagonist. "Notes on the Writing of Horror: A Story" is a bravura example of this, a horror story disguising itself (at first) as a essay on the craft of writing. It's a star turn, and one that ought not to work, but in Ligotti's hands it does, gracefully and effortlessly.

These stories appeared first in small press magazines with names like Nyctalops and Crypt of Cthulhu, and as a result Ligotti's strange talent has grown and blossomed far from public view. He comes before us fully developed and in peak form, the most startling and unexpected literary discovery since Clive Barker.

If there is a justification of genre, it lies here. For this book is the pure quill, core stuff, a shot straight from the heart of horror. It is difficult to imagine someone who doesn't love the genre properly enjoying Stories of a Dead Dreamer. Put this volume on the shelf right between H.P. Lovecraft and Edgar Allan Poe. Where it belongs. Michael Swanwick's most recent books are the novel "Stations of the Tide" and the short-story collection "Gravity's Angels," both forthcoming.