Four Werner Herzog moments: 1 The opening sequence of his 1972 film Aguirre, Wrath of God, so astonishingly other for a teenager in the acrid darkness of a 1970s London cinema. I remember the porcelain face of the Madonna in her glass box, then the camera reverse-zooming, so that we see the conquistadors strung out along the jungle path. Back and back the camera pulls, revealing more and more immensities of mountain. It's a perfect image: the European invaders, with their religious baggage, reduced to the status of ants crawling up a log.

2 An interview with one of Herzog's earlier wives in a documentary about the film-maker. She stands on some godforsaken Baltic coast, with the wind whipping her hair about her face; she is beautiful and mournful, and speaks of how they were married: "Then Werner left immediately to film in the Arctic for a year. He returned for a few weeks and then departed once more to film in central Africa. Then he came back to me, but he was editing mostly, then he left again ..." 3 Klaus Kinski interviewed on the set of Fitzcarraldo, Herzog's 1982 film about a man trying to build an opera house in the Amazon jungle, for the documentary about the making of the film (Burden of Dreams). The skullfaced actor appears haunted as he recounts how he threatened to walk off the set, but Herzog said to him: " 'This is a Mauser rifle with a 10-shot magazine before you reach that first bend in the river over there, nine of these bullets will be in your head!' And you know what, I completely believed him!" 4 The flat bled of Kuwait after the first Gulf war, the camera circling over the smoke-belching, flame-vomiting oil wells set on fire by the retreating Iraqi army. It's a scene of unearthly horror and beauty, heightened unbearably by the haunting majesty of the andante from Mahler's Resurrection Symphony that plays on the soundtrack an indissoluble marriage of image and sound..

These are a selection of my own Herzog moments, but I could have set down a score more. Of course, they may not be altogether accurately recalled, but I think the director will forgive me. When I taxed him with his public image as a tyrannical presence on the set, he bristled: "In that film [Burden of Dreams] there is no testimony, there is no witness who has ever seen me direct who has ever used the word 'tyrannical'. It's not unfair, it's outright wrong. I work like a surgeon doing openheart surgery. I am very quiet, very focused. That's it. You only hear the whispers on my set."

Possibly I should have said "fanatical", and although no doubt Herzog would have rebutted the charge born, I concede, of an overidentification between him and his protagonists he would probably not have minded. "That's okay," he told me, "that there are those doppelgängers out there other Herzogs. They're like guards who are protecting me." And Herzog must need protecting.

His restless energy (he is the only director to have shot on all seven continents) and the sheer grit required to get his films made would seem profoundly alienating and not only to wives. For film fans of my generation, Herzog, now 66, remains the most persistently maverick of the directors loosely grouped under the heading of the German new wave. Of course, what mostly tied Wim Wenders, Rainer Werner Fassbinder, Herzog and Jean-Marie Straub together was an accident of birth.

"It's commonly noted that we were a 'new wave'," Herzog said. "But I think only that we were the first generation of film-makers not involved in the Nazi time. That's the only denominator; otherwise I never belonged to my peers." Never belonged to his peers, and perhaps never belonged to any commonplace understanding of cinema.

For a decade or so, from Aguirre (1972) to Where the Green Ants Dream (1984), Herzog's films were mandatory viewing, but since then any kind of box-office success for his features has eluded him (not that I imagine he cares a jot). The surprising thing is that while such conventional fare has been returned to the creative kitchens uneaten, the director has made a feast of side dishes. Herzog has always made documentaries, to me he was forthright. "What's wrong with a novelist writing theatre plays, or poetry? In literature it's understood that people work in different genres." Of course, I conceded, this is understood in film as well; it's just that the allure of big features, and the associated studio system, seems to suck directors in like a digitally imaged black hole sucking in digitally imaged spacecraft. Herzog shrugged: "It's not the rule and I suppose I am pretty much the exception." But Herzog's sensibility the quest, as he describes it, "for the ecstatic truth" has always led him to point his camera at the natural world, and in particular to try to divine the changes that humankind has wrought upon it. Not that his films are straightforward eco-parables; rather, Herzog's ecstatic truth seems to be the highly charged reciprocal relationship between man and nature a classic case of German dialectics, although he refuses any easy synthesis. The film that includes the shots of burning oil wells, Lessons of Darkness (1992), had a forerunner in Fata Morgana (1971), which was shot in the Sahara, but neither are bare accounts.

"Lessons pretends to be a sci-fi film, but of course it's not," he says. "I prefaced the commentary with a quote from Pascal that I made up myself. We can talk for 48 hours about some great quest for inherent truth through sound and images, but I believe this is intrinsic to all films.

" Herzog has a reputation as forbidding and steely. While being interviewed by Mark Kermode for the BBC in 2006, the director was shot with an air gun by some La-La land freak and barely flinched, although he was wounded but I found him eminently approachable. When I asked him whether it had made any difference to his work that he was now living in LA, he replied warmly: "No, it hasn't!" Then made an abrupt volteface: "Yes, it has! I'm happily married here that's the reason why I'm here." He conceded, "Whether I live in Los Angeles is pretty much unknown to people", but continued: "Hollywood is looking at my work." The reason is that "over the past two decades, the studios may have developed great digital effects, they may have giant stars, but there is a deficit, I think, of storytelling, and because of that shortcoming, they are looking at my films".

Herzog is a glutton for work, and he was editing a new feature, shot in the States (My Son, My Son, What Have Ye Done?), when we spoke. He has also recently completed shooting Bad Lieutenant, an alternative version of the 1992 Abel Ferrara film starring Harvey Keitel. Characteristically, Herzog denies having seen Ferrara's version, and disputes that his is any kind of a remake. Herzog's Lieutenant stars Nicolas Cage: "I got the best performance out of him of his career.

I always get the best performances out of actors it's very important to me, it is essential to being a director." But while he extols this work, it is, I suspect, his 2005 documentary Grizzly Man, about the bizarre life and death of its antihero, Timothy Treadwell, that has gained him a new following. Grizzly Man was not unusual for a Herzog film in that it used "found footage" int his case, Treadwell's own film of his interactions with Alaskan grizzly bears, including a macabre soundtrack of him being mauled to death by them, which Herzog spares the viewer, though we see him listening to it himself on headphones. I asked Herzog if he felt any responsibility for the way he had made use of this material: "I think I portrayed Treadwell in a way that he would have accepted and liked.

He always wanted to be a big star and I gave him all the possibilities to be one. I gave him the big music and the platform. You do not do him any favours by simplifying this." What, I queried, about Treadwell's girlfriend, who also died, but is unnamed and uncredited? "Unfortunately, we couldn't have any statement from her family, so that's a blind spot in the film but it is what it is, and how shall I say? If you ever want to see into the deepest depths of human nature, into the abyss of our soul, just watch Grizzly Man.

" Herzog's latest feature-length documentary, Encounters at the End of the World, lacks the grisly bite of the last, nor does it seem to be simply another chapter of his search for ecstatic truth in a landscape. It owes its genesis to remarkable undersea (and under-ice) footage shot by Henry Kaiser, footage Herzog initially used in a curious sci-fi "epic", The Wild Blue Yonder (2005), where these luminous visions of a weightless and bouleversé world stand as proxies for another planet.

"I never plan a film the way someone plans a career," Herzog said. "I had a burning desire to go under the ice and film there myself, but it was denied." Instead, Kaiser shot more original footage for this film at two separate sites, where scientists are working beneath the Antarctic ice pack. Encounters has some spectacular footage of Antarctica, including never-before-seen views of the weird fumaroles in the volcano Erebus and more poignantly of the ugly environs of the American base at Mc- Murdo Sound. Although a keen polar buff myself, I'd never seen these kind of images before, something explained by the fact that although Herzog received an official US grant to go to Antarctica, his film was free from the usual vetting process.

But rather than being a film about the place, in common with others of his projects, Encounters is about the psychic interaction between humanity and place. Thus, his most poignant sequences are to-camera interviews with the people who work in Antarctica: proud Native American carpenters and truculent truck drivers plagued by wanderlust. Areclusive zoologist points out to the film-maker a suicidal emperor penguin, who, as if in a calculated riposte to the joyful anthropocentrism of Happy Feet, seems intent on walking away from the flock, out into the wastes and certain death. Encounters is whimsical, strange, oblique, with a filmic grammar that is wholly original wholly Herzog.

To me he conceded that while his interest in Antarctica came from the visual stimulus initially, he could empathise with Scott, Shackleton and the other early explorers. "Both Shackleton and Scott were flawed because of their obsession with the South Pole which takes away the beauty from places like these, reducing them to geographical abstractions. It's like Mount Everest leave the mountain in peace! Still, these two men embodied all that is best in the collective spirit of the Brits." With such a view of national character, it's no surprise that Herzog's view of the creative process is equally muscular.

With his astonishing work rate, I asked him how he felt about the films he had completed. "They are like burglars in the night who all of a sudden raid your home you've got to get them out! Or rather, you open the door to let one guest in, and suddenly 85 people are swarming all over you." When the unwanted guests burst in, I asked him, did he know if they were feature films or documentaries or, indeed, operas which he has been known to direct Watch the trailer for Encounters at the End of the World at timesonline.co.uk/film or books which he has been known to write (he has a new one out, about Fitzcarraldo, this summer)? "Only when I wrestle with them, and I feel their skin and sniff their scent, do I make a distinction."

So, there's Herzog: no tyrant on the set, but only a put-upon host, wrestling with fruitful creative demons. No chronic peripatetic "I don't know how I ended up making films all over the world, it is bizarre to me!" but only a joyful traveller, who, rather than seeing himself as a citizen of the world, told me he remains "completely Bavarian". And when I asked him what, for him, defined being Bavarian, he replied: "Take a film like Fitzcarraldo. Besides me, only King Ludwig of Bavaria could have made that film." I managed to restrain myself from pointing out that the epithet most commonly applied to this patron of Wagner was "mad".

C Encounters at the End of the World is on release nationwide; see review, page 14. Werner Herzog's book about the making of Fitzcarraldo, Conquest of the Useless, will be published in America on June 15 by Ecco

'He's never belonged to any commonplace understanding of cinema': Herzog Beneath the Antarctic ice pack in Encounters at the End of the World