Among the many tributes that the film critic J Hoberman received after he was fired by the Village Voice last month came one from a former student named Matt Singer. Now a writer and TV host, he compiled a list of the most important things he'd learned from a seminar Hoberman had taught as a side gig at New York University. It contained a good deal of sound advice  "Watch for excess words. If there's a shorter word, use it"; "Vent your spleen. In criticism, it's better to be angry than depressed"  but the most basic and important message was this: "Plot synopses automatically ruin a review."

Rightly or wrongly, the synopsis is regarded as one of the lowest forms of writing. Two-thirds of the way into Zona, his characteristically singular book about Andrei Tarkovsky's Stalker (1979), Geoff Dyer declares: "There are few things I hate more than when someone, in an attempt to persuade me to see a film, starts summarising it." Doing so has the effect of "destroying any chance of my ever going to see it". It's a surprising assertion  though less so if you're familiar with Dyer's books which, whether they're about jazz, the first world war or DH Lawrence, go out of their way to fuse form and content in arresting fashion  because Zona is one long movie summary, a shot-by-shot rewrite.

With a running time of just over 160 minutes Stalker is itself a long movie. Alongside Solaris (1972), it's the Russian film-maker's best-known work, tracking an arduous journey in which a middle-aged man known simply as the Stalker leads the Writer and the Professor through a militarised wasteland into a territory named "the Zone'", at the heart of which lies "the Room" that is said to grant the deepest wishes of anyone who steps inside.

Loosely based on a 1971 novella by the brothers Arkady and Boris Strugatsky, it's a science-fiction-tinged story whose apocalyptic setting and general hazards (gunfire, underground tunnels, sodden waterways), to say nothing of its quest motif, prefigured modern-day computer games. So much so that in 2007 a Ukrainian company issued a first-person shooter game entitled S.T.A.L.K.E.R. that was partly inspired by it.

With its cast of shaven-headed men who resemble Gulag inmates, its blasted topographies and its posing of fundamental questions about human happiness, Tarkovsky's film has often been interpreted as an allegory of life under communism. Dyer, who has diligently ploughed through a great deal of the critical commentary Stalker has inspired, not only flags up that particular reading, but draws attention to how it can be seen as a prophetic work that anticipates the zones of exclusion drawn up in the wake of the Chernobyl disaster in 1986.

But Dyer, for all his chafing against the parochialism of what passes for intellectual culture in this country, and even though many of his essays and books are set abroad, has always been an English writer. This expresses itself in the tone of Zona, so that, as much as he portrays the Stalker and his companions as metaphysical pioneers, they also come across as stumbling chumps straight out of the pages of Jerome K Jerome's Three Men In A Boat.

Equally, though there are ample references to Merleau-Ponty, iek and Heidegger, these are offset  or complemented  by stray putdowns of Jeremy Clarkson ("The Zone is a place of uncompromised and unblemished value. It is one of the few territories left where the rights to Top Gear have not been sold") and casually entertaining footnotes, one of which quotes Mick Jagger's thoughts about Jean-Luc Godard with whom he'd just finished working on Sympathy for the Devil: "He's such a fucking twat."

Some readers may find these riffs and asides more whimsical than enlightening. Some might be wondering too if Dyer's ever-evolving genius for comic writing now leaves him no time or desire to pursue the bruised lyricism that lit up earlier works such as The Colour of Memory (1989) and Paris Trance (1998). What's certainly true is that hardcore cineastes weaned on, say, David Bordwell's cognitive film theory will find Zona a little undercooked. Would Dyer care? If his characterisation in Out of Sheer Rage (1997) of academic criticism as wilfully sterile onanism is anything to go by, I suspect not.

For myself, I think it's rather wonderful that he is writing about Tarkovsky in a manner that is as colloquial as it is learned. Dyer rescues him from the clutches of the arthouse crowd, depedestalises him, draws connections between the ruined landscapes in Stalker and the brambly, abandoned train station at Leckhampton, near which he grew up in the 1960s.

At a time when David Cameron appears to regard The King's Speech as the acme of film-making, and any art that's remotely ambitious is derided as obscurantist or elitist by middle England's cultural gatekeepers, it's especially important to stress that interested film-goers can enjoy works more challenging than The Inbetweeners Movie.

It's equally pleasing to read Dyer speak up for the pleasures of watching films, not in domesticated and tamed form on DVD, but at the cinema. Stalker itself, which is an immersive experience as much as it's a visual spectacle, loses its magnetic force when watched at home. Dyer talks about the "possibility of cinema as semi-permanent pilgrimage site". He also claims "the Zone is cinema."

Beyond the book's bravura formalism and in spite of the suspicion that it could be viewed as a highbrow take on live-blogging, it's Dyer's ability at moments like this to make pilgrims of his readers and to lead them on a journey in search of truths about love and about the nature of happiness that make Zona such an exhilarating achievement.

 Sukhdev Sandhu's Night Haunts is published by Verso.

The films of Andrei Tarkovsky, and in particular his 1979 classic Stalker, have a reputation for being among the most difficult in cinema. Difficult, not just in the sense of intellectually demanding, but difficult as in hard to sit through, long and slow-moving and potentially very boring. Perhaps only the work of the Hungarian director Béla Tarr is viewed (or not, in most cases) with greater trepidation. Cinema buffs wear their familiarity with films such as Stalker and Tarr's seven-hour Sátántangó like a badge of honour and speak of them in reverential tones. Most other people regard them like non-mountaineers regard Everest: "I'm sure it's a great mountain, but damned if I'm climbing it."

In his new book, Geoff Dyer sets out to address this problem by articulating what he loves so much about Stalker in terms that won't alienate the casual viewer. Zona is an intriguing proposition: Dyer writes about the film in something approaching real time, describing each scene as it happens  almost like a DVD commentary  and pausing at regular intervals to reflect on the making of Stalker, on other films and other works of art, on being Geoff Dyer, and on being Geoff Dyer writing this book about Stalker. Despite operating on many layers, it's not a long book. A fast reader could polish it off in less time than it would take to watch the film itself (163 minutes).

Dyer first saw Stalker in his 20s and, though "slightly bored and unmoved" by it on that first viewing, he has returned to the film obsessively ever since. It may be a great monument looming formidably over 20th-century cinema, but to Dyer it is also a compelling human story that has proved inexhaustibly relevant to his own life and has informed (sometimes in a spookily prophetic way) how we view the world around us.

Tarkovsky's film tells the story of three men breaking into a mysterious sealed-off Zone in an unnamed country (presumably the USSR) and journeying to the even-more-mysterious Room at its heart  a place where, it is said, one's innermost wishes will be granted. Stalker is the name of the guide who leads the group.

It's billed as science-fiction, but if you watched the film with the sound off you'd think it was just three guys wandering around a debris-ridden area of countryside, grumbling at one another. And that may actually be the case: we're never sure if the Zone really does have magical powers, or whether Stalker's tales are merely the kind of superstitions that grow up around areas fenced off by the government. This uncertainty opens up a space for the Russian director to explore some of his favourite themes: the hopelessness of life; the generative power of belief; the plight of the visionary misunderstood by all.

In many ways, Dyer is the perfect man for the job of unpicking the complex mysteries of Tarkovsky's Zone. He has a rare talent for writing about high-minded concerns with disarming simplicity, and he is unafraid to mix in a bit of low culture so that on one page he'll be reflecting on Top Gear or regretting that he's never had a threesome, while on the next he's going on in the same breezy fashion about Brueghel or William James. What makes him a pleasure to read, particularly here in the inner sanctum of high cinema, is that he isn't oppressed by the need to be reverential. On the contrary, he'll crack as many bad jokes as he can about Stalker's nagging wife, or the granting of innermost wishes, en route to the transcendent truth. As the Camus quote at the front of the book says: "The best way of talking about what you love is to speak of it lightly."

By treating the characters in Stalker as tragicomic everymen, rather than figures in a great text, Dyer brings out the humour and humanity in Tarkovsky's work. It would be a mistake, though, to suppose that he is doing this  beating an accessible path into the Zone  for our benefit alone. He tells us: "There are writers for whom commentary is absolutely central to their own creative project, who insist that at some level commentary can turn out to be every bit as original as the primary work of the novelist." This is a reasonable definition of what Dyer has been doing for most of his career  in his radically digressive study of DH Lawrence, Out of Sheer Rage, for instance  and it's what he pulls off again with considerable flair here.

This, in other words, is much more than a useful guide to a classic film. It is also, in small doses, a memoir, a rumination on art and a philosophy of how to live well. Moreover, it is a running commentary on itself, and as such it poses a problem for the reviewer. Dyer is forever pre-empting criticism by flagging up the potential shortcomings of his project: wouldn't he have been better off writing a book about tennis? Now and then, he draws attention to the patchiness of his own research: he only "skimmed" the Stanislaw Lem novel that Tarkovsky's Solaris is based on and decided to avoid his final film The Sacrifice; an explanation he gives about a patricide in a recent film indebted to Tarkovsky is, he confesses, "one part Harold Bloom and one part ill-digested psychoanalysis".

This, of course, is part of the raffish, easy-going charm of his writing and a source of its comic effect. No other writer cops out quite as elegantly as Geoff Dyer. However, there are passages in the book  especially towards the end when he seems to tire of summarising the onscreen action  that feel merely dashed-off, rather than strategically lazy. The segues begin to feel forced and jokes fall flat. A dog laps at milk "like there's no tomorrow", offending against Dyer's earlier observation that the Zone is a sanctuary against cliche. It was an inspired decision to write a book about one of cinema's most austere works in a relaxed, throwaway style, but that's no justification for slapdash writing.

That said, I'm glad he undertook the journey. Even if you have zero desire to experience Tarkovsky's film first-hand, it's worth keeping company with Dyer for the tangents it sends him off on: an explanation of why the horror film Antichrist, which Lars von Trier dedicated to Tarkovsky, is "nonsense"; or the funny and poignant footnote about how Natascha McElhone in the remake of Solaris looked uncannily, at the time of its release, like Dyer's wife.

But if you've never seen Stalker, I'd urge you to watch it for the final scene alone. I agree with Dyer that it brings us to "a realm of loveliness unmatched anywhere else in cinema". It casts a miraculous light back across the rest of the film and makes the effort of scaling this great rock of cinematic art utterly worthwhile.