For the last 20 years, we in the West have been reading the genres of Anxiety, but it may be that there is a new increase in that fever as we approach the century's end.

Though the years of a century may be real enough -- a year being the time it takes a planet to orbit a sun -- the climax called Millennium that we have constructed out of these accumulated orbits is almost entirely a tissue of dreams and numerology. The Millennium is what happens when a species with 10 fingers chooses to count on them. This is not, of course, the whole story.

The Millennium we are about to enter is not simply the arbitrary outcome of a biological accident. It has become a powerful symbol for a momentum we fear has become too great, a dark abyss of futurity into which we're plunging too fast to understand. Symbols, of course, are not "real." But they shape the minds that create them. The Millennium is an active, potent symbol generated by a species that has gained the power to make its symbols work for it. We are a species named Frankenstein.

So this fever at century's end has substance. It shapes our imaginations, and our imaginations shape the world. It is, as well, a fever with a pedigree. Beneath the current, hectic faddishness about the Millennium lie two centuries of obsession with Time in the Western World, an obsession whose roots are many (though the French Revolution may mark its first significant historical moment) and whose manifestations are nearly infinite. We're going to concentrate here on the stories we tell ourselves for fun and profit, the stories we tell to divert ourselves from the darkness ahead.

It was just before the year 1800 -- which is the first century-marker in the West to gain widespread attention -- that the clock of Time Manifest began to tick, and the engine of history began visibly to turn. Citizens of the Western World began to doubt the scriptures that had told us nothing was new under the sun, that the human race had no choice but to repeat the great stories the Lord laid down for us. We began to feel the ground of the world shift, as though it moved to a different drummer from God. Time past became immeasurably deep. Time present was rewritten utterly (by the ideologues of the French Revolution, who wiped the slate clean and began the world again with a brand-new calendar). And the future was invented: We began to believe that things were going to change. In daylight, we call that change Progress; at night, we do not.

At night time, from around the year 1800 on, the citizens of the West began to have bad dreams about living on the brink of things. Our lords and masters -- who write the script for our daytime activities, for our weddings and our jobs, our wars and occasional moments of peace -- could not acknowledge the existence of these dreams. (In 1999, they still refuse to admit that the peoples of the affluent West, regardless of the miracles of Progress, continue to act as though the world were in fact falling apart.) At night time, we know better than our masters.

So it is not surprising that, around the year 1800, Western literature began to change. It is around this time, in other words, give or take a decade or two, that what one might call the genres of Anxiety were born. These genres are generally known today as science fiction, fantasy, horror and crime.

Here is the moment when it all comes together: We are at the beginning of a novel. A strange, haunted mechanical figure is seen trudging across the sublime awfulness of the Arctic waste, burdened by more than human anxieties. He is a creation -- his master, Dr. Frankenstein, has constructed him out of body parts. The novel in which he appears, Mary Shelley's Frankenstein, or the Modern Prometheus (1818), is therefore a science fiction novel, perhaps the first. But Frankenstein's creation is also a monster, a clockwork doppelganger out of the poor doctor's (and the world's) worst nightmares, in which the inanimate becomes animate and steals our substance (and our wives) from us, as in the contemporaneous stories of E.T.A. Hoffmann. He is an early vision out of horror literature, a genre haunted by evil twins who well up into consciousness from the fissures of a world that has suddenly become unsound. He is also a creation of myth, a misshapen Trickster bringing a gift of strange fire from the new worlds of futurity; and in this sense Frankenstein is also one of the first fantasy novels ever written. And he has committed crimes, and he is being hunted down; he prefigures all the haunted wanderers of the 19th and 20th century, from Melmoth to Marlowe (Conrad's and Chandler's both).

Frankenstein is a text that exudes anxiety about the past, the present and the future. It is the perfect text to stand at the beginning of the genres of Anxiety that have tickled and allayed and diverted us from the fear of change, a fear that is natural to a species -- like all of the species on Earth -- which must recognize the surrounding world in order to survive.

Science fiction normalizes the changing world by claiming that things can be made to work, that there are fixes to mend the damage, that if we keep our balance and look forward to tomorrow we will come through. For traditional science fiction writers and readers, the story of the last two centuries is the story of how we may come to own change. For them, the Millennium looms as a judgment-marker on our success or failure in the grand human enterprise of conquest. For science fiction writers of a richer complexion of mind -- they include Kim Stanley Robinson, Neal Stephenson, Bruce Sterling, Gene Wolfe -- the technological fixes science fiction has espoused seem at best dubious, at worst fatal to life on the planet. But these writers have, perhaps, begun to transcend the genre they were born within.

Horror allays our anxieties by embodying them in stories whose main purpose seems to be to make the back of our neck tingle. I think this is only a very small part of the enterprise of horror literature. Great horror novelists, like Shelley, Bram Stoker, Stephen King and Peter Straub, are half-secretly on to something much deeper. I think they are trying to tell us that the evil twins who haunt us, that the secrets from the past that constantly threaten to rip our skins off our backs and expose us to eternities of violation, are nothing but tame visions out of the cauldron of story; that the truth behind the doors of Year 2000 (or behind other doors we may discern) is far more dreadful than anything the past might conjure up. The secret horror that these novelists convey is the suspicion that the evil twin is not behind us but in front of us. That the world beyond the Millennium may be a shattered world, an eggshell that could not sustain our terrible tread.

Fantasy is more forthright than horror. Fantasy novelists like J.R.R. Tolkien -- whose The Lord of the Rings (1954-55) is almost certainly the most widely influential fiction written in English during the 20th century -- or Steven Donaldson or John Crowley or Robert Holdstockall make it clear indeed that they think something has gone very wrong with the world. For fantasy writers, the dislocating changes of the years since 1800 are just as distressing as the visions of apocalypse kicked into life by our current obsession with the Year 2000. For them, the 20th century has been wrong from the get-go; and the greatest fantasy novels allay our anxieties through the creation of other worlds that directly contradict the official stories our masters tell us of Progress and Speed and Uniformity.

It is easy to think of the crime novel as reaching its apogee in the classic detective comedies of writers like Arthur Conan Doyle or Agatha Christie or Rex Stout. In thousands of tales by these great figures and their colleagues, a detective comes upon a crime that has dislocated the world -- exposed the chaos beneath the workings of daylight society -- and by solving the crime knits that world back together again. But the true history of the crime novel features other writers -- Shelley, Edgar Allan Poe, Dostoyevsky, Kafka, Chandler, Ross Macdonald -- and their best stories come dangerously close to letting the cat out of the bag. Macdonald or James Lee Burke or a lesser known (but immensely darker) English writer, the late Derek Raymond, almost explicitly tell us that there is, after all, something wrong in the very taste of the world we try to recognize. Something wrong in the very way we try to cope. Crime novels tell us that the footprints we leave on the eggshell of our fragile world are marks of sin.

Almost everything published in 1999 in any of the four genres of anxiety is, of course, retro junk. In fact, any work in any of the four genres over the last 200 years has, of course, to some extent, a narcotic effect. Science fiction and horror and fantasy and crime stories came into existence, after all, in order to address and to allay our fear of time changing.

But the times are indeed changing. We are entering a world -- the world we symbolize by the Millennium -- of such mutability and stress that we may need new narcotics to survive the strange nights of tomorrow. It may be that the genres themselves, which have done so much to soothe our brows, have reached the end of their usefulness. There are some indications this is so. The craze for retro in all four genres is an almost certain sign of heat death. The merging of the genres destroys much of each genre's prophylactic function. And so forth. This may be inevitable; indeed it surely is. Two centuries is a long time. But questions arise for which there are no easy answers. What are we going to do when our stories are dead? What are we going to tell ourselves tomorrow?

John Clute's latest publication is "The Book of End Times: Grappling with the Millennium," forthcoming in October.