 Towards the end of 1996, one of Gabriel Orozco's lungs collapsed. It was a freak occurrence and, after a painful week in hospital, the artist spent the winter convalescing in New York. For someone used to continually travelling the world, it was a testing time. But during this period of enforced recovery, Orozco created one of his most recognisable and profound works of art: Black Kites.  Once seen, this piece is not easily forgotten. It consists of a real human skull on which Orozco painstakingly drew a checkerboard-like grid in heavy graphite. as the drawing delves into the eye sockets, and loops across the bumps of the cranium, the skull's knobbly surfaces and cavities distort the regimented squares of the design. Orozco completed the pattern after six months. 'I remember, when I finished, I thought it was kind of horrible, really weird. a shocking thing,' he says. 'I couldn't see it any more so I put it in the closet and left it there.' Black Kites belongs to the tradition of the memento mori, but it also alludes to the prevalence of decorated skulls in the art and popular culture of Mexico, where Orozco was born in 1962. It is also a sophisticated meditation on the processes of thought. The geometrical grid stands for knowledge, learning and rational deliberation; the skull stands for the strangeness of organic reality and the inevitability of death. Culture and nature are opposed, yet melded together; one cannot escape the other.  Later this month, Black Kites will be shown as part of an important retrospective of Orozco's work at Tate Modern in London, where it will present a fine example of the dense poetic effect that the artist has been summoning since he first excited curators and dealers around the world in the early 1990s. But although it is one of Orozco's most familiar pieces, Black Kites is not especially representative of his wider work. Indeed, it is hard to point to a single work that is emblematic of his style. Primarily a sculptor, Orozco also produces drawings, paintings, photographs and installations.  No two works by him look the same: a 1960s Citro?n car sliced lengthways into three parts and then meticulously reassembled, minus the central section; an oval billiard table without any pockets; a photograph of a sleeping dog: all of these are part of his extensive repertoire.  He is forever reinventing himself and surprising his audience. Some of his artistic statements are modest, such as the melon that he placed on a shelf in the bookshop of London's Institute of Contemporary arts when he exhibited there early in his career in 1993. Some are spectacular, like the skeleton of a whale that he decorated with a drawing and suspended in the national library in Mexico City four years ago.  In his infinite variety, Orozco perpetually eludes the esoteric formulations of art critics, who tie themselves up in knots attempting to define his work. Yet he is one of the most respected contemporary artists working anywhere in the world today. The Tate retrospective will be the latest incarnation of an exhibition that has already travelled to Paris, Basel and New York, where it originated at the prestigious Museum of Modern art. Orozco is only 48, but already he has achieved a level of recognition usually reserved for grand old masters.  During the 1990s, Orozco earned a reputation as an artistic nomad. He resisted being labelled as a Mexican artist, but equally refused to be pigeonholed as part of a new generation of artists from New York, which became his adopted city when he started renting a small apartment there in 1992.  Instead, he travelled the world, carrying little more than a toothbrush, a notebook and an automatic Nikon camera. He started producing work that reflected his perpetual migration, wandering from one medium to another. He used foreign banknotes and airline ticket stubs as surfaces for drawings and paintings. He made sculptures out of cars and bicycles, suggesting ceaseless motion. He even exhibited his own suitcase.  He once fashioned his own weight in Plasticine into a giant, greasy, lopsided sphere, and rolled it down Broadway in New York before placing it inside a nearby museum, so that the malleable material became encrusted with dust and debris, and marked with the impressions of everything that it had touched. (Yielding Stone, as this piece is called, can be understood as a self-portrait of the protean contemporary artist, whose life is continually in transit, and who is forever open to chance encounters with the world.) Throughout these years, famously, Orozco never had a proper studio, preferring to work quickly, on the move, inspired by his ever-changing surroundings.  Yet nearly two decades on, the nomad has become a man of property. as well as New York, which is where I meet him, Orozco owns homes in Mexico City, Paris and rural France, where he spends his summers. His house in New York, an attractive brownstone reportedly worth nearly $9 million, is situated in the West Village, an affluent and artistic district of Lower Manhattan. Orozco's next-door neighbour is the Brazilian model Gisele B?ndchen.  after ringing the doorbell, I am greeted by a maid, who guides me through a beautiful reception room strewn with the leftovers of a birthday party for Orozco's six-year-old son, Sim?n, his only child with Maria Gutierrez, whom he married in 1994. I discover Orozco inside his kitchen, eating lunch. (Gutierrez, who works for the Climate Change Secretariat of the United Nations, is in her study upstairs.) Orozco has tanned skin, unruly grey hair and a beard. He wears tortoiseshell sunglasses, and absent-mindedly plays with an elastic band on his wrist as he talks.  There are no formalities, and he begins the interview at once. He wants to make it clear that, despite the trappings of substantial success, he feels as unencumbered as he did when he left Mexico City in his mid-twenties to spend a year in Madrid.  'I am changing all the time,' he says, while tucking into a steaming cactus stew. 'I travel between my houses, and still have no primary studio. Mostly I draw and plan in my notebook, so my notebook is my studio. I change so much from project to project that even if I had a studio I wouldn't know what tools to have or what type of assistant to employ.' He pauses, picks up a knife and dissects an avocado.  'The idea of a workshop has never appealed to me,' he continues. 'For me, it's important to move, and to leave my work exposed to things I don't know. For each project I do something different. I make things - provisional things - and the only thing that is consistent is that I travel on my own and do things on my own.' He smiles ruefully. 'Look: I am even eating alone.'  To understand the reasons for Orozco's restlessness, you need to understand the context in which he grew up, and against which he fashioned himself as an artist. Orozco was born in Jalapa, in the eastern Mexican province of Veracruz. His mother was a classical pianist. His father was a communist, and a third-generation mural painter in the tradition of Mexican artists such as Jos? Clemente Orozco (no relation) and Diego Rivera.  The history of Mexican art, though, left Orozco cold. 'I was very tired of this image of Mexico as a Surrealist country,' he says, referring to the paintings of Frida Kahlo. 'Mexican culture is permeated by this exoticism of reality - which I don't find to be true, and is not important to me. I find Surrealism boring.'  Orozco attended art school in Mexico City, but was frustrated by its parochial conservatism. In 1986 he moved to Madrid, where he learnt about the work of avant-garde artists such as Robert Smithson and Gordon Matta-Clark, and studied an emerging generation of British sculptors, including Tony Cragg and antony Gormley. He also became enamoured with the american modernist composer and polymath John Cage.  'I remember reading a small booklet about John Cage and getting very excited by his Zen attitudes about art and life, and the use of chance encounters and provocations and accidents.' On returning from Madrid, Orozco began a series of simple, rough-and-ready sculptures, including Recaptured Nature (1990), a misshapen rubber sphere patched together from the inner tubes of salvaged truck tyres, and My Hands are My Heart (1991), a lump of brick clay which he squeezed into the approximate shape of a human heart.  Both works engaged with the world in an unaffected, modest manner: Orozco was subtly refashioning reality, rather than making something 'exotic', and using materials not usually associated with 'high' art. They were shown in his first major international exhibition, a group show at the Royal Museum of Fine arts in antwerp in 1992.  Orozco also developed  a burgeoning interest in photography (he had used a camera to document Mexico City's ruined streets in the aftermath of the earthquake that killed 10,000 people in 1985). His pictures look like casual snapshots, but are in fact highly orchestrated. Crazy Tourist (1991), for instance, depicts an empty Brazilian market, abandoned except for a number of oranges carefully positioned on ramshackle wooden stalls as far as the eye can see.  In his sculpture and photography, Orozco was honing an aesthetic that favoured cheap, improvisational gestures, instead of anything more substantial. He would often build temporary sculptures out of detritus that he encountered in the street; he would photograph these objects, dismantle them, and move on.  In doing so, he was deliberately reacting against the prevailing contemporary art scene in New York, which had been characterised by overblown, expensive pieces by artists who always seemed to have one eye on the market.  'There were many things about the way of doing art in the 1980s that I was not so crazy about,' Orozco says. 'It was the climax of market speculation, and the objects were made to behave in a market of commodities. They were trying to impress with shininess, as products. Obviously Jeff Koons is one of the main characters of this type of art. I was sceptical of art like this, and still am. I also found it really tedious - stiff, dead, not intriguing. So my work started to do something different.'  One thing Orozco reacted against was 'the obsession with the big studio in which you have all this space to create: the glamour of the artist selling for millions of dollars and having a big loft in SoHo. at that time, the dream for many artists was to come to New York, have a big loft and become famous. I was not so impressed by that - particularly coming from an art world family. So I remember saying, it's not about having money, it's about what mentality you have. I found it much more interesting to be out in the street, engaging with everyday life.'  Orozco still believes that the art market can have a negative effect on artists. 'In general, I think the market makes art very bombastic,' he says. 'I try not to follow that path. There are many other ways to do art.'  The way Orozco likes to 'do' art is to keep in touch with reality. 'It's not about screaming at people or trying to mesmerise people with spectacular strategies. I believe that a small gesture can have a much bigger impact.'  after the art market crashed in 1990, Orozco's unostentatious approach won him many admirers. He was like a prophet who had been preaching humility under the decadence of the Romans and, by 1993, he was inundated with offers to exhibit at respected institutions around the world. at that year's Venice Biennale, he provocatively showed an empty white cardboard shoebox placed on top of its own lid - the antithesis of the baroque aesthetic of the 1980s. He was also invited to mount a show at New York's Museum of Modern art. In the empty space between the escalators he unfurled Dial Tone (1992), a Japanese scroll decorated with dense columns of numbers cut and pasted from a Mexican phone book.  Towards the end of 1993, he created one of his biggest, most dramatic pieces: La DS, the sliced-up Citro?n that is a distillation of sleek, streamlined speed. In contrast, the following year, for his first solo exhibition in a commercial space in New York, he bemused onlookers by showing nothing but four transparent plastic yogurt pot lids, stamped with sell-by dates and price tags, attached to the four walls of the Marian Goodman Gallery. Yogurt Caps (1994) has since been hailed as a courageous masterstroke of conceptual art. Does Orozco see any connection between these early successes? How does he join the dots of such a varied career? 'I have no idea,' he says. 'I don't think in those terms at all. One of the things that people recognise about me is that I change all the time. They don't know what to expect for the next exhibition. They only know that it's probably going to be different from the last one.'  He pauses. 'That was not always easy for people to accept. Maybe they were expecting me to cut more cars, or to go on to cut a truck, and then cut an airplane. You know, when you have a piece that has some success, you can develop a line of production based on it that will definitely have a life in the market and please the crowds.'  So why did he resist following such an easy path? 'Because I get bored,' he says. 'I don't want to be doing the same thing again and again. I wake up and I like to do something different, something that makes me feel intrigued. I enjoy research, I like to learn new techniques, and every idea demands a different approach. I am a person who has many interests. I like a bit of science, a bit of philosophy, politics, sports.' Indeed, Orozco is a keen player of football and ch 