Journalists and critics are always bending over backwards to find creative superlatives to describe the Quebecois theatre artist and filmmaker, Robert Lepage. He is a "wizard" (the Guardian), a "spellbinder" (the Daily Telegraph), a "visionary" (the Evening Standard), a "superhero" (the Montreal Gazette).

But, as the latest chapter of Lepage's career unfolds, perhaps the best description of his role in contemporary culture is that of tour guide. For if, as social anthropologist James Clifford has said, "travel and the state of being between cultures" is what most characterises contemporary living, and if theatre exists to reflect, refract and engage with what's happening in the world around us, then there's no one out there more creatively responsive to, nor more able to lead us through these travel-obsessed times than Lepage.

Lepage's stage work has always, in some way, engaged with themes of travel - his first major work, The Dragon's Trilogy, was set in a series of Canadian Chinatowns. "I was fascinated by the idea," Lepage has said, "that you can cross the road and enter this dream world, this vision of China." Tectonic Plates was inspired by the notion of continental drift, and followed a young Quebecoise on a life-changing trip to Venice. Lepage performed Needles and Opium suspended in a harness above the stage, representing both Miles Davis's drug trips and a famous plane journey that Jean Cocteau took to America. And The Seven Streams of the River Ota was nothing less than a travelogue of the late 20th century, a seven-hour epic which followed an extended family from the bombing of Hiroshima to the Nazi concentration camps, through 1960s New York all the way up to the here and now.

His current piece, The Far Side of the Moon, takes the theme to new extremes - to outer space, as it happens. Far Side, which Lepage wrote, directed and performs, is currently playing at the Royal National Theatre (RNT) in London. It is set during the space race in the 1950s and 1960s, and is filled with filmed images of the first space walk and clever representations of astronauts and rockets (one of the latter created by a Pringles tin, a coffee flask, and a salt shaker). But the Soviet/American competition to be the first to penetrate the cosmos serves mainly as a background metaphor for a more immediate, personal and accessible story: of two brothers, both played by Lepage, who are apparent opposites and who are forced to confont and start to overcome their differences after their mother dies.

Lepage's work has always been fuelled by his own interests and experiences, but this is doubtless his most intimate and personal piece to date: his mother died two years ago, and his father only a few years before that. "I spent a year researching this thing," he told the Guardian, "and at the same time my mother dies and I have to deal with this new reality that both my parents are dead. I see that all these things are connected. That whole moon theme and feeling that you are drifting if you lose your parents - all these elements come crashing into one another." Far from being an indulgent escape into the confessional, Far Side feels like a landmark work in Lepage's oeuvre. In recent years, there's a sense that he's been creatively adrift: his last large-scale collaborative piece, The Geometry of Miracles, about an unlikely connection between the American architect Frank Lloyd Wright and the Russian mystic Georgi Gurdgieff, never really came together; some of his smaller-scale directing work, such as a staging of Mahler's Kindertotenlieder and a Tempest in Quebec for which the audience wore 3-D glasses, was judged to be under-realised, even gimmicky. He's been struggling to establish himself as a filmmaker: although his first film, Le Confessional, was something of an arthouse hit, his second and third, Polygraphe and N⌠, have failed to find significant audiences outside of Canada.

But with Far Side there's a sense that Lepage is back on track, back creating a kind of theatre that taps into the preoccupations of the collective consciousness through visual and sensory means, as well as through text and performance. It has certainly reingratiated him to the British critical establishment, who, it seemed, would never forgive him for the seriously undercooked world premiΦre of The Seven Streams in Edinburgh in 1994, for which, one of the show's actors now admits, the cast members were so unprepared that they had to improvise about one-third of their lines on the spot. Nor were the British critics amused when, two years later, Lepage cancelled the Edinburgh premiΦre of his one-man Hamlet, Elsinore, less than an hour before the performance was scheduled to begin. That cancellation was blamed on a fault with the show's elaborate set, and Elsinore did eventually get on its feet. It visited the Dublin theatre festival in 1997, where it divided critics and audiences; some loved its technology-heavy re-envisioning of Shakespeare's world of suspicion and surveillance, while others found its pace ponderous and its treatment of the play itself distractingly inconclusive. Elsinore was only the second of Lepage's works to visit Ireland; Galway arts festival audiences may remember the Irish premiΦre of The Dragon's Trilogy in 1989.

What anchors The Far Side of the Moon is Lepage's extraordinary confidence and appeal as a performer: the show is more than two hours long without an interval, and Lepage is onstage virtually non-stop; spectacular visual and technological effects are played against his hyper-realistic acting that wouldn't be out of place in film or on television. And, oh, the visual imagery. The show is set in a long, narrow, horizontal playing space with a round porthole in the back wall which, in the first scene, represents a washing machine in which Philippe, our nerdy failed-scientist protagonist, is washing his recently deceased mother's clothes. We see him sort his colours from his whites from two perspectives, for there is a live video camera behind the porthole which plays back the "mirror image" of Lepage's actions. At one stage he sticks his head, then his whole body, into the washer: and then we see his floating image projected on the back wall: he has become an astronaut, drifting in space.

Such unexpected shifts in perspective and in the identity and use of objects is one of Lepage's trademarks, and here he's spinning visual metaphors at a rate of knots: images of doubles, reflections, seeing oneself in one's opposite mount throughout the performance: the porthole becomes a goldfish bowl, the window of an airplane, and the moon; and Lepage plays not only the two brothers but, in two magnificently moving scenes, their late mother as well.

Lepage's personal horizons seem remarkably rosy at present. Now 43, he lives, when he's not touring, in his hometown of Quebec with his partner, American actor and writer Kevin McCoy; his personal affairs are handled by his younger sister, Lynda Beaulieu, to whom Lepage has said he owes his career, if not his sanity - it was she who, when he was suffering from profound adolescent agoraphobia, forced him into a taxi to appear in his first high school acting gig. He has been performing Far Side for 17 months in more than 20 international venues, but this London engagement will be the last with the show: he is rehearsing another actor, Yves Jacques, to perform the role on a further international tour. His latest film, Possible Worlds, premiΦred last Friday in Britain. A thriller (Lepage's preferred filmic genre) which, following a mysterious death, plays out different scenarios between the deceased and his beloved (played by Tilda Swinton), it is earning Lepage some of the best reviews of his film-making career.

Next up, theatre-wise, Lepage is collaborating for the second time with one of his artistic heroes, Peter Gabriel, whose "Secret World" concert tour Lepage staged in the mid-1990s. This show's title, "Zulu Time", would seem to indicate that Lepage is accompanying Gabriel on one of his Real World voyages into African culture; but in fact the phrase is, of all things, an aeronautical reference - it's another name for Greenwich Mean Time. The new show is a "techno-cabaret" set in an airport-like space; according to the show's London-based producer, Michael Morris, it's about "the experience of transit. More than a theatre piece it's a gig, really; it's not based around text or character and will appeal to a younger kind of audience. It's different than anything Robert has done before." The show is made up of 26 individual vignettes or bits of action (one for each letter of the aeronautical alphabet), which will be performed in different configurations throughout the show's life. "Zulu Time" will play at New York's Roseland Ballroom in September, and Morris says that London dates will be likely next year.

As a hugely successful, globetrotting, 21st century theatre artist, Lepage spends much of his time in transit. This is doubtless a double-edged sword: he gets to see and engage with the world, but he also must feel, much of the time, like he's floating, rootless, in space. But rather than turn against this experience, he has turned it into material. It's hard to imagine a more universally evocative representation of the contemporary human condition than a person wandering alone in an airport, waiting for a disembodied voice to announce what the next move should be.

Lepage is directly connected to that zeitgeist. As we navigate the globalisation of culture, his work provides a road map.

Possible Worlds will be screened at the IFC, Dublin, in October.