Of course, this kind of immediate, almost blinding sensual appeal is perhaps the central power of film. Movie stars have always been sex symbols; movies have always been about attraction and arousal, however subliminal. All of which has made – or has helped to make – LotR a dubious yet irresistible proposition for moviemakers. One or another of them has been in pursuit of the book since 1957, doubtless drawn not merely by the tale's enduring literary popularity but also by its scale and grandeur: the dramatic landscapes of Middle-earth and the wildly diverse creatures who roam there, not to mention the heroic quest of the story's small hero, the hobbit Frodo, who, like Christ, suffers dreadfully and alone so that those he loves do not have to.

Elijah Wood makes a beautiful and fetching Frodo: that soft youthful skin, the luxuriant mop of dark curly hair, those wide blue eyes. He has a slightly early-Beatles look; you can almost hear the teen girls shrieking. Yet the beautiful blue eyes register fear for most of The Fellowship of the Ring (the first of the film's three installments), when they are not registering bafflement or pain. Wood's Frodo has the look of a small animal enduring torture, and while it's impossible not to feel for him, it's also hard not to be aware – at least for those (very many) of us who've read the book – that a dignity and uncomplaining stalwartness at the core of Tolkien's Frodo have somehow been misplaced by Wood and director Peter Jackson.

I wonder if this doesn't have something to do with the film's overwhelming visual potency. Movies emphasize carnality (how could they not?), yet LotR is really a story of moral conflict, spiritual strength, courage – qualities that do not lend themselves to visual representation. Jackson is certainly aware of this problem, but he has no real solution for it; he's read the text too literally, so that when, for example, he tries to show the spiritual power of the Lady Galadriel, he turns her into a glowing white icon, as if she's some kind of phosphorescent Christmas ornament instead of the subtly starlit elven queen she is in the book. The effect is, sad to say, hokey.

The worst moment in the film – Gandalf's fight with the Balrog on the bridge of Khazad-dûm – should have been the best. In the book the emotional impact of Gandalf's fall and the scattered survivors' attempts to save themselves is almost unbearable. But the movie, first, does horrific violence to the Balrog, which becomes, in the hands of special-effects geeks with far too much time and money on their hands, a ludicrous fire-breathing, fanged hunchback that looks as if it has escaped from Jurassic Park instead of being the "fiery shadow" Tolkien described: "What it was could not be seen: it was like a great shadow, in the middle of which was a dark form, of man-shape maybe, yet greater; and a power and a terror seemed to be in it and go before it."

The very vagueness of the book's description is part of the Balrog's power and, in a broader sense, is part of the emotional charge the written tale earns page by page. The movie Balrog's appearance, on the other hand, causes, like an earthquake, a sharp and unexpected shock. But shock is a sensation, not an emotion, so that when the surviving companions gained their freedom and immediately started weeping for Gandalf, I found myself wondering – through my own tears, for as a close reader of the book I was already equipped with the necessary emotional substructure to be devastated – whether the moment made any sense at all on its own terms, whether the movie had earned the emotional response it so urgently demanded.

Yet the film's rendering of the Mines of Moria – a kind of underground Roman ruin, like a buried Ephesus, with endless rows of stone columns – is staggering in its gloomy splendor. So is Lothlórien, the Golden Wood, glimpsed on the horizon as a shimmering haze; and the rolling, homey green of the Shire; and the mighty Argonath, the Gates of Gondor, two towering sentinels cut from stone on either shore of Anduin. Rivendell is all wrong: too precious, and Hugh Weaving as Master Elrond (mysteriously referred to in the movie as "Lord Elrond") is a scold with perpetually furrowed brows – unrecognizable. But the movie's landscapes on the whole are a formidable achievement and might well impress Tolkien himself.

Which is not to say that Tolkien would approve of the movie, or was in any way a movie lover. He wasn't. His imagination was notably precinematic; he spent his youth learning Gothic and Latin in the company of enthusiastic schoolmates, and then fighting in the trenches of World War I in the company of similarly beleaguered young men. His was a literary world of profound and enduring male companionability, and he very much re-created that dynamic in LotR, where, in a world beset by darkness and danger, love exists almost exclusively between males: Bilbo and Frodo, Frodo and Sam, Frodo and Aragorn.

The Fellowship of the Ring is almost three hours long, and yet it often feels truncated and rushed. The visual wizardry of the movie cannot make up for everything that's been left out or is simply unfilmable. Neither can the fleshly allure of the characters. But that allure does leave you wondering, as Kirk and Spock always did, whether those loving male characters feel each other's carnal pull as strongly as we do – strongly, because we don't and can't feel much else.