Tate Modern, London SE1
In his self-portraits, Paul Gauguin invariably viewed the world askance, his heavy features angled away from his audience, his increasingly wolfish eyes slanted back to observe the viewer. The pose gives him an estranging, sly character, and that is also the sense of the artist that pervades this remarkable exhibition (which runs until 16 January 2011). You thought you knew Gauguin? You didn't know the half of him.
The biographical details are familiar enough: the stockbroker son of a South American revolutionary family, Gauguin was for a long time a Sunday painter, but in his late thirties he abandoned his wife and five children in Copenhagen and took himself off to follow his vision of a life more vivid, first in France, and then in the South Seas. His mid-life climacteric led him to seek the company of Cézanne and Pissarro. Van Gogh, lusting for life and death, wanted to make him the leader of a post-impressionist revolutionary movement at Arles. Typically, he resisted every attempt to contain him.
Some of the most unnerving paintings in this show are those he made while his extremes of wanderlust were still just inside his head. The domestic subjects of his early canvases are always trespassed upon by disconcerting interlopers from other worlds; innocence and home are under siege. The sleeping head of his son Clovis lies on a table beside a huge beer tankard, and curious phantoms and winged creatures seem to take flight from the wallpaper between these two dreamy vessels. In another painting, his youngest daughter lies asleep on a cot with her nightdress hitched up around her, a strange black mannequin at her bedside.
Gauguin seemed to have become obsessed in this period with images of severed heads, as if wanting to remove and destroy the darker thoughts circulating in his own. His ceramics were characterised by the demonic little self-portrait of a toby jug he made, a decapitated vision of himself that could be filled with liquor. Elsewhere, shifty idols stare out from behind painted vases and fruit bowls with Gauguin's eyes and no necks. A side of ham on a platter becomes more bloody with looking than any head of John the Baptist. And behind a matronly portrait of one Madame Alexandre Kohler, the artist sneaks in a vision of a piece of pottery with three rat-headed horns rising from a weird hunk of meat.
The disturbing incongruities that you see in these paintings put all that follows - in particular the vaunted "exoticism" and "sensuality" of Gauguin's South Sea vision - in a wholly different light. The Breton paintings, in which he starts to find his Tahitian palette, seem haunted as much by a sense of complicated transgression as any liberation into colour.
There is a telling pair of paintings of the same coastal headland. In one, a field is being threshed. In the other, the wheat has been replaced by a young nude in the foreground, stroking a hunting dog, while the middle distance in which a family congregates is as blood red as Gauguin's ham on a plate. One painting is called Harvest, the other The Loss of Virginity.
What the exhibition and its attendant collection of letters and illustrative material demonstrate is that Gauguin not only carried all this psychological freight with him to Tahiti; he also took with him a riddling sense of his self-image, a highly marketable persona that he nourished and distrusted by turns. The paintings of native girls in their lost Eden for which he became renowned are in many ways a consummation of a struggle that gives all of his work its mesmerising charge.
What sets Gauguin apart from Van Gogh is his capacity sometimes to see the human comedy of that battle. This distancing irony comes across most often in the arch titles he gave to his Tahitian work - in his stunning portrait of two slightly knowing, possibly post-coital nudes by a riverbank, say, which asks (perhaps of the salon-goers back home): "What! Are you jealous?" The old demons are never too far away, however. The images of his sleeping children have been replaced by images of his recumbent lovers, and the person who watches over them has become a vision of death (characterised in Manao tupapau as a hooded idol, with Gauguin's own aslant eye).
The longer he stayed abroad, the less at home Gauguin seems to have felt. It is a slightly chilling thing to see the carved gates to his jungle house displayed here so far from their natural habitat. By the time he made them, in 1902, the year before he died of syphilis and alcoholism, he was depicting himself as a horny, clawed and crouching figure in the background to paintings such as Primitive Tales. He called his home Maison du jouir - the House of Pleasure - but, as this unmissable show makes clear, it was never simply that.
For more details, visit: tate.org.uk/modern