Who is Michael Myers? What is he? I refer to Michael Myers: not the funny one from Austin Powers: International Man of Mystery. But the other one: the local man of mystery who has made life so difficult for the residents of Haddonfield, Illinois.

We first saw him as a six-year-old boy holding a knife, in the opening sequence of John Carpenter's Halloween (1978). Michael, who had just slain his sister, was locked away for good. Needless to say, he escaped, and the movie caught up with him as he came back to town.

Now a strapping lad in a white rubber mask, he spent the best part of ninety minutes trying to kill seventeen-year-old Laurie Strode (Jamie Lee Curtis).

He failed, and returned to the chase in Halloween II (1981), in which we learned that Laurie was his other sister.

Five sequels - of rapidly diminishing worth - made you wonder what exactly Michael's business strategy was. Now the man is here again, in Halloween: H2O (1998), pitting himself against Laurie one last time.

Whether "man" is the right word is open to debate. In the credits of the original picture, he was listed as "The Shape"- a name that hinted at diabolical powers of transmutation, though to modern ears it makes him sound like a supermodel. ("Laurie wanted to kick Shape's ass," John Carpenter told me approvingly.)

In the latest installment, our heroine summons Michael with the cry of "Psycho!," which is at once a nod to movie buffs and an indictment of his mental state. Dr. Sam Loomis (Donald Pleasence), who tried to treat Michael and ended up tracking him through the course of several films, had little luck with such delicate psychological terms.

In the first movie, he referred to his former patient as "the evil"; by the time of Halloween 4, he had narrowed this down to "evil on two legs."

The new picture, directed by Steve Miner, is subtitled H2O (1998) not because Michael has decided to slip something nasty into Haddenfield's water supply but simply because twenty years have passed since Carpenter's film. You could be forgiven for thinking that the Halloween franchise was dead and buried, but in 1996 Wes Craven's Scream raised it smartly from the grave.

Scream climaxed with the villains' stabbing themselves for the sake of an alibi - an ideal image for the bewildering narcissism of the whole enterprise, in which a variety of clean-cut students either suffered or perpetrated violence through a tangle of movie references.

Specifically, they were all worshippers of Halloween, and of the rigor with which it observes the rules of horror. One of the more unbendable rules states that, whenever the television is switched on in a scary film, another scary film will be playing; its never golf or Home Shopping, although both have terrors of their own.

During Scream, we kept seeing Jamie Lee Curtis's face flickering in the corner of the room; she was still there when Neve Campbell, with a nice easy follow-through, crunched the TV set onto the killers head.

With a plug like that, it was inevitable that Michael and Laurie would be dusted down and brought out to play. Its a relief to see Curtis back in the series again, not just because she has been AWOL since Halloween II, but because she makes such a welcome change from all those kids. I find the teenagers of Scream wholly interchangeable; it is hard to be mortified by the demise of those who have given little evidence of living.

Curtis was hardly more than a kid herself in Halloween, but there was always an uncommon gravity in those long-boned, elegant features: she was at once more virginal than the jocks and bimbos around her and more adult - less convinced by the notion of the world as a playground, especially after it turned into a charnel house. Now in H2O, she has grown into a single mother, a secret drinker, and (under an assumed name) the headmistress of a school in Summer Glen, California.

The movie delves into her fraught relations with her son, who has reached the same age that Laurie was in the first movie; her experience in Haddonfield was, as Curtis dryly put it to me recently, "not without its fallout." There is no mention in H2O of Jamie, Laurie's little girl, whom the bogeyman pursued in Halloween 4. In the final shot of that picture, Jamie herself was gripped by demonic possession, clasping a long knife, just like her uncle Michael. What is it with this family?

There were two reasons why I did not see Halloween when it came out. First, I was not legally old enough to do so, and second, I wouldn't have been caught dead at a horror flick. When you are in the full flush of juvenile movie snobbery, you don't go and see films that excite you for an hour and a half; you go and see films that bore your socks off for three hours, on the medicinal principle that they must be good for you.

Scornful of Illinois, I preferred movies that were either set north of Hamburg or east of Prague, and replaced orthodox narrative with at least three of the following: a dream sequence, a dwarf, a clown removing his makeup, a religious crisis, and/or a nude bathing scene. After three years and much huffing, however, I was persuaded to skip the new Tarkovsky and see Halloween instead.

And that was that.

By now, I must have seen the movie twelve or thirteen times, but, on that first viewing, most of the in-jokes remained too 'in' for me. I did not yet know that Jamie Lee Curtis was the daughter of Janet Leigh, or that Sam Loomis was named after the John Gavin character in PSYCHO.

I got no sneaky countercultural thrill from the fact that Halloween had cost only three hundred thousand dollars. (It has since recouped that sum a hundred and fifty times over.) I didnt even realize that Michael's headgear was a spare William Shatner mask from Star Trek: The Original Series.

All I knew was that this guy Myers had parked in my head and was refusing to move on. I couldnt shake the four-note mantra of the score (composed by Carpenter himself) or the even less florid piano theme - a one finger plink - that accompanies Michael's arrival at the head of the stairs.

Indeed, the whole movie seemed to work in dotted crotchets: as you braced yourself for a fright, Carpenter would hold for an instant and then let fly, just as you were relaxing into the delusion that nothing was going to happen. It was a method inherited from Hitchcock, and it barely survives in today's movies, which tend to deliver their traumas right on time.

Best of all, there was Laurie's infamous slump and slide against a wall. The wall takes up half the screen - the other half is shadow - and we know that Michael will jump out of it. But he doesn't jump; he fades into view. The white face slowly glimmers out of the dark like a memory that you have struggled to recover. Or like a ghost who is bashful of his own remorseless power to scare.

The sound in the movie theatre at that moment was like nothing I had heard before: a rising siren moan, not unmixed with pleasure. Carpenter had taken an old and cloudy conceit - the maniac on the loose - and distilled it to something pure and clean. Tarkovsky would have wept.

Carpenter's achievement was to suggest that there was nothing exotic about horror; that is was more inbred than outlandish; and that it was best considered as the evil twin of what one might call the lyrical conservation of American movies. "There's no place like home," intones Dorothy, and yet Oz is peopled with figures adapted from those whom she loved - and feared - in Kansas.

And what of Meet Me in St. Louis, a rapturous hymn to the comforts of the known which suddenly dispatches one of its elect, Tootie, into the awesome ritual of Halloween? Carpenter's film may be said to have sprung from Tootie's fevered dreams; I like to think that she grew up, married, and had a grandson named Michael.

That is why, after Halloween, small towns - not just those in the movies - looked like paradises lost. If JAWS made us check the blue pleasure ground of the sea every time we dipped our toes in, Halloween made us wonder whether suburban houses, set back peacefully from the road, were quite the refuge that had always been promised.

Laurie runs from one door to the next, trying to rouse sleepy householders with her howls; finally, she is alone with Michael in a single dark dwelling.

When they grapple on the second floor and she pulls off his white rubber mask, the man underneath is more like a boy - a farm boy, almost, with broad, puffy features, who looks rather surprised to be exposed in this way. "Was it the bogeyman?" Laurie asks in the last lines of the movie. "As a matter of fact, it was," says Loomis.

The good doctor is onto something: Michael Myers is a matter of fact. In the world proposed by the film, he is part of the landscape, or the furniture. Even when Loomis puts six bullets in him, he simply moves on.

These days, such a beautifully smooth gear change into the supernatural would look like a cute setup for a sequel, but Carpenter had no such plans; he just wanted Michael to stay out there, biding his time. ("An O. Henry ending," the director calls it now.)

That is why a movie that started with the pantherish glide of a Steadicam closes with still shots of all the places - the corners, the stairs - where Michael has been, and where he may yet come again. There's no place like home.

Freud, as usual, was on the case long before movies got there. In his 1919 essay The Uncanny, he demonstrated, via inspired linguistic sleuthing, that heimlich (homely) and unheimlich (uncanny) are on a collision course, and that at some point they mean the same thing.

Both words whisper of secrecy and concealment, and they lead Freud toward what any moviegoer would recognize as the full robes and trappings of horror: the inanimate that dawns into life, the perplexing appearance of a double, the action that unnerves by repetition - all those occasions on which the familiar grows strange.

The problem with horror flicks, of course, and the reason so many of them disappoint, is the speed with which the strange becomes not just familiar but a total drag.

For every Halloween, with its effortless if unwitting dramatization of Freudian themes, there was a Nightmare on Elm Street Part Four or a Friday the 13th: The Final Chapter, which itself was swiftly followed - and, you might think, severely compromised - by Friday the 13th Part V: A New Beginning.

The presiding irony of horror is that, while no genre offers more imaginative license, few of the directors - or, indeed, the novelists - who turn to it have more than a thimbleful of imagination in the first place. (They have a sweet tooth for the fantastic and the glutinous, which is hardly the same thing.)

When visionaries and obsessives deign to frighten us, on the other hand, the results can be spectacular: look at Murnau's Nosferatu, Dreyer's Vampyr, or the Karloff Frankenstein pictures (which redefined horror as a species of warped romance).

Neither Fritz Lang nor Bunuel ever made a straight horror movie, and yet all their work is laced with the horrific; the Peter Lorre of M is both a serial killer and the cowering victim of his own monstrosity.

As for Hitchcock and lesser masters such as Jacques Tourneur (the director of the original Cat People), their movies are mischievous and oddly puritan; Hitch sometimes feels like the torturer who tickles your soles with a feather while his poker warms in the fire. John Carpenter is best seen, I think, as the last of that breed.

Halloween may have spawned some bastard children, but in fact it glances back longingly to the nineteen forties and fifties - to an age when it was enough to scare us as efficiently as possible.

If people screamed loud enough, the deeper and more pungent fears would seep out. Now it is 1998, and what is there to be scared of?

I attended a sneak preview of H2O at the Gotham on Third Avenue in New York. I bought my gallon pail of Coke, took my seat, and stared around. It didn't really matter if the movie spooked me or not, because I was already terrified by the audience. It seemed unlikely that any of them had seen Halloween when it first came out, for the simple reason that none of them had been born yet.

They made me feel seventy-five years old, a sensation enhanced by the opening credits. Janet Leigh has a cameo in the movie ("If I could be maternal for a moment," she says to Jamie Lee Curtis). But her name drew no response; when LL Cool J came up, on the other hand, the place exploded.

You could argue that this was no more than an update of 1978, when Carpenter specialists had snickered at Sam Loomis; but the Gotham was not full of specialists. It was full of moviegoers, and what gave me the creeps was not what they knew, or what they didnt know, but what they didn't care to feel. To them, H2O was a comedy - a little black round the edges, sure, but basically a scream.

Miner's film is far bloodier than Halloween, whose severe lack of ketchup was a tribute not merely to its budget restrictions but also to Carpenter's feeling for the sore spot. (Blood is not frightening; what worries people is the uncertain certainty that it might be shed.)

But the kids laughed at the gore, whooped at the shocks, and left the theatre in merriment. All those George Bush-period warnings about media desensitization suddenly seemed a little less crusty than before.

One more layer of innocence had peeled away here: not the innocence of joy but the even more primal innocence that allows us to be terrified. It asks that we revisit, however briefly, the nightmares that first enfolded us in the nursery, when patterns on the wallpaper assumed shapes and rocking rhythms of their own.

If you are seventeen in America today, however, with no serious bogeyman in your life, what could possibly be less cool than slipping back into infancy? Why bother to be scared out of your wits when wits are both your plumage and your claws?

In keeping with my newfound senescence, I was scared by H2O. It is plainly the only serious Halloween movie since Carpenter's original, and Miner stokes his tale into a kind of glowing dread.

The script, like that of Scream, keeps winking at the audience, but Jamie Lee Curtis, to her immense credit, plays it with a straight and stricken face. Halloween was stripped to the bone and untroubled by motives, whereas H2O labors under the fleshy weight of the past.

To put it crudely, Laurie is now as much of a head case as Michael himself, and you feel the thunder in the air when they meet face to face. They gaze at each other through a small round window; it resembles a porthole, or a looking glass, and it brings sharply to mind what Freud said of the double - that it is the "uncanny harbinger of death."

You realize that Michael has become, if not a mirror image of Laurie, then the other half of her being: he cannot live without her. And she cannot truly live until he dies.

No wonder, as the finale looms, that Laurie declines to flee; instead, she takes an axe and marches back to the fray. The camera rises high to watch her go, as if she were Gary Cooper in High Noon.

Jamie Lee Curtis described this scene to me as "strapping on the guns." She went on, "By running, Laurie is never going to redeem her soul, but if she turns around and faces the person who took away everything that would have given her pleasure - her ability to trust, to love - then what she gains by the act is to get her soul back."

This may sound heavy, but the moment itself is, as Curtis puts it, "weightless." With the end in sight, after all these years of Michael, "you feel high, on some level free."

As a matter of fact, you do.