Year's Best SF 6 edited by David G. Hartwell, Eos, 2001, 500 pages, $7.50

The Year's Best Science Fiction: Eighteenth Annual Collection edited by Gardner Dozois, St. Martin's Griffin, 2001, 617 pages, $18.95

In "Reality Check," a brief story by David Brin – published in the science journal Nature and reprinted in David Hartwell's Year's Best SF 6 – the godlike minds of the future look back with envy at our times, when there were still so many unanswered questions, still so much work to do. Every creative enterprise offers finite possibilities, Brin tells us – "only so many eight-bar melodies can be written in any particular musical tradition" – and over time the available "invention space" gets used up. Later generations have increasingly smaller patches in which to work, and eventually there's just not much interesting left to do.

The demolitionists of Robert Silverberg's "The Millennium Express" (also included in Hartwell's volume) travel the world destroying monuments and treasures of every type: the Sistine Chapel, the Taj Mahal, the Parthenon, the Washington Monument, the sunken ruins of Istanbul. It's not that they despise the relics of earlier centuries; it's the very greatness of this cultural heritage that demands its destruction. The vandals believe that their own generation has been ruined by "the iron hand of the past," by the weight of so much accumulated achievement. "Where's today's great art?" one of them asks. "Where are our great works? It's as though our famous forebears have done it all and nothing's left for us to attempt."

As the giants of the field continue to pass into history – in 2001 Poul Anderson and Gordon Dickson joined the pantheon of the departed – it might be tempting to wonder whether the futures imagined by Brin and Silverberg present a parable of the current state of science fiction. Some might say all the good ideas have already been used. The early masters covered most of the conceptual territory: space travel, alien planets, first contact, future war, time travel. Today's writers are left to work out variations, and the excitement of discovery has disappeared.

There may be a little truth to this. Certainly it's a different proposition to write in a well-established tradition than to carve that territory out of the literary wilderness. It's a lot harder now to get away with stories that offer little more than a neat concept. But the fact that most of the SF landscape has been mapped, at least on a large scale, need not leave us in the despair of Brin's all-knowing ennuists. Pioneering days may be gone, but the invention space has hardly been exhausted.

Indeed, the work in SF today may well outshine its rougher antecedents. What we lose in great leaps of invention we gain in richness and complexity, as writers dig into the implications of the ideas glimpsed by their predecessors. Time travel is no longer news, but its convolutions can still fuel a hundred – or a thousand, or ten thousand – wonderful stories.

The vigor of SF is abundantly clear in both Hartwell's Year's Best SF 6 and Gardner Dozois's The Year's Best Science Fiction: Eighteenth Annual Collection. Despite – or thanks to – divergent aesthetics, these two volumes reveal a thriving literary ecosystem. Sf continues to shift and evolve; it becomes ever more diverse in tone, style, and substance; yet it retains its ties to its ancestors, just as our own cells recall the shapes of their lonely progenitors a billion years gone.

The selections in Hartwell's volume favor that phylum of SF that emphasizes ideas over other fictive values. Hartwell includes seven pieces from Nature's series of short-short stories, and few of them – as Hartwell acknowledges – work very well as stories in the usual sense. They're thought-pieces, SF notions presented using the devices of fiction. They're certainly good for a quick kick of science-fictional thinking, but they're SF with every other literary pleasure boiled away.

Some of Hartwell's remaining selections demonstrate that today's SF can still be heavy on concept without ignoring other dimensions of storytelling, none more compellingly than Ted Chiang's novella "Seventy-Two Letters." As he did in his Nebula-winning first published story, "Tower of Babylon," Chiang gives us a world in which the erroneous scientific notions of a past era are instead correct, and he develops the implications in delightfully convincing detail. In "Seventy-Two Letters," cabbalistic magic – the stuff that brought the Golem of Prague to life – combines with medieval biological theory to create an alternate Industrial Revolution and a weird shadow of genetics. Chiang conjures some wonderful images – factories powered by tireless ceramic statues, children playing with mini-golems like wind-up toys – but it's the rigor with which he has worked out the rules of this other science that amazes and amuses most. Next time you hear someone complain that there are no new ideas in SF anymore, hand 'em "Seventy-Two Letters" and a plate of crow.

Not every idea-focused story here produces as vivid a world as Chiang's, but they're all stimulating in their own ways. Brian Stableford's "The Last Supper" imagines dinner at the haute cuisine establishment of the genetically modified future, with sharp wit and a coolly analytical courtship driving the tale. "Different Kinds of Darkness" by David Langford involves mathematical patterns that can kill on sight (think of Monty Python's "killer joke" without the laughs), and the school kids who make an initiation rite out of enduring them. In "Sheena 5," Stephen Baxter proposes squid as the Earth creature best adapted for space travel, and humans perhaps little more than the engine of their uplift.

Greg Egan's "Oracle" is an idea story of a different order. It's not the SF conceit that's on stage here – that's a pretty standard time travel scenario, with a little extra theorizing on the branchings of parallel worlds. Egan uses this familiar setup to juxtapose two characters of radically different philosophies, based on the British mathematician Alan Turing and the medievalist, fantasist, and popular theologian C. S. Lewis. It's a staged debate – at the story's crux it literally comes down to one – during which the Turing character argues for the validity and even the spiritually redemptive quality of the rational materialist worldview, while the Lewis character, wrapped in grief for his dying wife, rejects science and its seemingly miraculous works as lures designed to break his faith. The results aren't exactly a surprise, but the story succeeds on Egan's eloquent exposition of the opposing points of view, and on his sensitivity to the fundamental objection at the heart of most rejections of science: its powerlessness to address certain deep human concerns. By treating the anti-science arguments with a measure of respect, Egan produces a more convincing rebuttal, and a more involving story.

Hartwell makes a respectable effort to include work that covers the wider range of SF as it's written today. Stories by Howard Waldrop, Robert Reed, Ursula K. Le Guin, M. Shayne Bell, and others fall less squarely in the realm of idea-oriented SF. But the backbone of Year's Best SF 6 remains the idea story, and that aesthetic pervades the book as a whole. Hartwell's selections reveal an SF field in close touch with its roots, with plenty of intellectual heat left in its traditional modes, but without the lush otherworldliness of Jack Vance or Cordwainer Smith.

This other strain is much better represented in Gardner Dozois's annual volume, the eighteenth incarnation of his reliable Year's Best Science Fiction series. This isn't to say that Dozois's book is devoid of exciting new SF notions, or new twists on old ones; but Dozois seems more interested in SF's ability to produce exotic and peculiar people, settings, and situations. For instance, "Radiant Green Star" by Lucius Shepard displays Shepard's characteristic richness of language and description as he follows a twenty-first century circus through the Vietnamese countryside. The figure of Major Boyette, one of the circus's main attractions, will remain indelibly in the reader's mind as the sort of phantasmagoric entity only possible in SF: "the last surviving POW of the American War, now well over a hundred years old and horribly disfigured," the major crouches in his tent like an ancient oracular ape, grasping at shattered memories. The story's images, and Shepard's rolling, rhythmic prose, conjure a fascination that the plot and ideas themselves would not create.

Albert Cowdrey's "Crux" shows us a future in which an imposingly complex, highly mannered interstellar civilization has grown up in the deserts of Central Asia, centuries after the collapse of our own world. It's a heady mixture, in which the languid freelance security agent Steffens Aleksandr anaesthetizes himself with kif and dallies with the courtesan Dzunn at the Radiant Love House; where lawbreakers vanish into the terrible cells of the Palace of Justice; where alien Darksiders hold the guardposts and the common tongue is a doggerel of Russian, English, and a dozen other languages, called Alspeke. It almost doesn't matter what the story's about with a kaleidoscopic setting like that.

Ian McDonald draws on material much closer to home for a landscape nearly as strange in "Tendeléo's Story." Here the Africa of the very near future has been struck by mysterious alien meteorites which have proceeded to transform the terrain and everything on it in a steady, implacable expansion from the impact points. The transformed zones – called the Chaga – lie offstage for most of the story. McDonald finds plenty of gritty alien detail in the human world of Africa, as bizarre as Shepard's future Vietnam and as familiar as yesterday's front page.

Occasionally the dazzle of an exotic surface masks an otherwise sub-standard tale. "Obsidian Harvest" by Rick Cook and Ernest Hogan is a pulpy detective story taking place in a world where the Aztec drove off Cortez and his Spaniards, and Mesoamerican civilization grew to dominate the New World. As if that didn't provide enough color, South America is home here to a race of saurians, the huetlacoatl, who maintain delicate relations with humans of the north. For the most part the tongue-tying names and interesting cultural quirks offer sufficient distraction, but as the plot works itself out it descends nearly into camp. Likewise, it's only the grandiosity of the title structure of "The Great Wall of Mars" by Alastair Reynolds that redeems this otherwise choppy, uneven piece.

Dozois also displays more interest than Hartwell in the ways SF can be used to enhance or support literary purposes more commonly associated with non-genre fiction – stories in which the SF element may be faint or far from the center. Susan Palwick's "Going After Bobo" extends the current technology of implantable ID chips only a little – adding GPS tracking features – to create a world in which criminal offenders of every sort can be under surveillance at all times, and missing pets can be located by satellite. But this minor element of speculation helps Palwick develop a very moving story of family dynamics and grief, nudging reality just a bit out of kilter so that we can see things more clearly.

The aesthetic differences between Hartwell and Dozois are hardly all-encompassing. Several stories appear in both volumes, and some stories that only appear in one could very well have appeared in the other without skewing that collection's internal consistency. Dozois also includes Egan's "Oracle," for instance, and in his introduction he says he would likely have chosen Chiang's "Seventy-Two Letters" but that he felt it had to be defined as fantasy rather than science fiction, and that's a distinction Dozois works hard to maintain in his annual collection.

The stories that appear in both volumes tend to be among the most fully satisfying, because to appeal to each editor's aesthetic they need to work well on more than one level. "The Birthday of the World" by Ursula K. Le Guin fits very much into the honored tradition of anthropological SF, and it addresses the central SF theme of the clash between old and new, as a staid conservative alien culture struggles with internal change and the arrival of visitors from space. It's easy to see why it drew Hartwell's eye. But Le Guin's story advances as much through its narrator's emotional responses as it does through action, and that attention to subtleties of character makes it fit comfortably into Dozois's book as well.

Similarly, Paul McAuley's "Reef" offers many of the pleasures of a classic space story, set as it is amongst the asteroidal debris of the Kuiper Belt. It centers on a complex ecosystem of hardy "chemoautotrophic vacuum organisms" living in a deep chasm of a Kuiper planetoid, and this complicated ecosystem allows for plenty of scientific speculation and vivid description, as researchers dive – by remote-controlled proxy and in person – into the chasm to explore its mysteries. Again, it's not hard to see why both editors included this one.

The difference between the two aesthetics emerges most instructively in a comparison of two stories unique to their own volumes: "Built Upon the Sands of Time" by Michael Flynn in Hartwell's book, and "The Real World" by Steven Utley in Dozois's. The two pieces have similar themes, but they're radically different in tone, storytelling strategy, and emotional effect. Flynn sets his story in a bar, and laces it with the kind of beery witticisms and broad characterization you'd expect. His prose affects a wee bit o' the Irish local flavor – not poorly, but it makes the tale feel rather self-consciously told. Amidst the banter of the regulars emerges the story of a physicist from the local university, who lectures his barmates on how random fluctuations in the "quantum foam" can lead to sudden changes in the past – which then propagate forward through time, rewriting history in accordance with the new condition. This is how we end up with the odd lapses of memory and feelings of jamais vu that we usually dismiss as errors on our parts. Really, says the physicist, these are accurate memories of a past that is in the process of altering itself – fossils of a past that never was.

The physicist has been haunted by memories like this that have a distinctly more persistent cast, and he's convinced that, in a previous past, he discovered a way to cause such quantum disruptions, and that he did so in a fit of unhappiness with his marriage – thereby undoing that marriage, and the child born to it, leaving him in his bachelor state with ghostly memories of the history that wasn't.

Utley's story follows a scientist, Ivan Kelly, a specialist in ancient soils, on a visit to his screenwriter brother in Hollywood. Kelly was one of the first people to cross through a portal into what appears to be Earth during the Silurian age, many millions of years before the dinosaurs. And that trip has left him with an unsettling legacy. All the theorists examining the portal explained that the other side couldn't be the actual Silurian period on the actual Earth; travel into the past is impossible, so this must be a parallel world of some kind, so far indistinguishable from the Earth as it existed 400 million years before.

The problem is that, if the portal links parallel worlds differing perhaps only in some infinitely tiny detail, how can you be sure that the Earth you come back to is really the same Earth that you left? Since he's returned, Kelly has become increasingly worried that he's not in the same universe from which he departed. But he can't be sure. Unless the difference were big and obvious, how would he know? So he's growing detached, feeling alienated, but unable even to be sure if his notion is correct.

Both stories present time travel scenarios (time tinkering, perhaps, in Flynn's case) that leave the traveler or tinkerer cut off from his own past – stuck in a world he believes is not the one he left, but unable due to the uncertainties inherent in the process to ever know if his inkling is correct. But that's as far as the similarities go. Flynn's story focuses on the concept, even to the point of inserting simple diagrams to illustrate the physicist's point. The bar setting, the joking of the listeners, and the punchline ending – effective as it is – take the focus away from the emotional significance of the physicist's situation. Utley, on the other hand, takes care to describe his scenario with some technical precision, but he keeps his attention on the inner life of the central character. Even the humorous bits – Kelly attends a Hollywood party with his brother, where things are as surreal as any reader would expect – add to the feeling of unreality surrounding Kelly. Where Flynn tells his story in broad strokes, Utley chooses subtle details. Both of them are well-crafted and effective – though for my money I prefer the Utley, which leaves a stronger presence in the mind – and they're both clearly SF, but they occupy spots on distant branches of the family tree.

This is where we can see the strength of SF as a literary genre – or genera, to preserve the biological metaphor. We're not facing the exhaustion of the invention space, the closing of the frontier. Instead, more of it is available today than at any previous time, because exploring the space means carving a path. Every big idea that comes along – alternate history, say, or terraforming – opens up a new niche, and dozens of new branches can grow into it where none had been before. In Hartwell's Year's Best SF 6, we can see how the family lines of traditional SF continue to flower today, and in Dozois's Year's Best Science Fiction we can see how new species have sprung up over the years, new ways of using SF that could never have been had the pioneers not blazed some trails first.

Dozois's lengthy introduction – his annual "summation" of events in the field – raises some familiar but worrisome issues. Magazine circulations continue to shrink; some publications close up altogether; online venues for short SF have yet to demonstrate any financial legs. Only time can tell what the future holds for the SF short story. But we can be sure, from the work gathered in these best-of-the-year volumes, that the gene pool is healthy and diverse, and that gives any organism a good shot at survival.