`Odilon Redon: Dreams and Visions' is at the Royal Academy, London W1, from 17 February; `Odilon Redon' is published by Thames and Hudson, price £48
One should not," according to Galateo, a 16th-century Italian handbook of courtly manners, "weary others with such low matter as dreams, especially stupid ones, which most dreams are." It is not hard to guess what its author would make of Odilon Redon (1840-1916) - an artist whose oeuvre seems almost entirely devoted to dreams. Huysmans, an early promoter of Redon's work and the author of Against Nature, the manual of Decadent etiquette, dubbed him "the prince of mysterious dreams". He was paying a deserved complimentand one that suited Redon's tenebrous excursions into the subconscious; yet the near tautology of the phrase "mysterious dreams" also puts the case against him. Redon was born and brought up in the Gironde, in southwestern France, at a time when peasants in thick furs could still be seen perched high on stilts guarding their flocks. This paradoxical image, juxtaposing the earthbound and the airborne, is given a variety of obsessive, metaphorical twists throughout his work. As the scion of Peyrelebade, a wine-growing estate, his childhood should have been privileged but, perhaps because of his epilepsy, perhaps because of other tensions within the family, the young Redon was farmed out to an uncle and, as he remarked in his journal A Soi-Mme, felt like an outcast from his bourgeois family; indeed, he was brought up beside the children of the peasants. His identification with "the people", as he referred to them, was fortified by a period of conscription into the army dur-ing the Franco-Prussian war of 1870. His slow development as an artist, hindered both by misplaced literary ambitions and by persistent crises of confidence in his abilities, was given a decisive push forwards by the death of his father, who had acted as an inhibiting factor in Redon's life. His career began to flourish in his late thirties with the publication of his first lithographic album, Dans le Rve and he started to receive recognition from Huysmans and other writers of stature. At this point, Redon recorded, "I then made lots of drawings, abundantly for myself, for myself only, for the sole joy that their happening gave me." Ultimately, it was his mastery of charcoal, and later of transfer lithography (a method of printing from stone) that accommodated tentative smoky effects, which allowed Redon to trust to the peculiar-ities of his vision. The creatures he brought forth have a dual or divided nature: centaurs, sphinxes, winged horses, spiders or plants with human faces, decapitated Johannine heads. What lifts these images above the merely macabre is the lugubrious humour and sympathy which Redon feels, and transmits, for his hybrids and monsters. His charcoal Cyclops, for example, as though unaware of its spiky mane, idiot grin and thick features, turns its lone eye poignantly towards the heavens. And Cactus Man is a typical Redon creation, a transitional life-form with its own grotesque dignity, part pot plant, part jack-in-the-box. Redon's interest in the microscope and in protozoic forms was much encouraged by his friend the botanist Armand Clavaud. It was especially gratifying to Redon that the great biologist Pasteur, to whom he sent Dans le Rve, responded by pronouncing Redon's monsters "fit to live". It's not that Redon turned dreams into art, but rather that he found an equivalent state in his art: an uncertain, suspended, floating consciousness out of which images unexpectedly appear. Redon's themes are narrow and - with the exception of landscapesand his later flower paintings and saccharine portrait commissions - they are drawn from mythology and fantasy. He produced thousands of black-and-white images - noirs as he called them - but his drawing lacks the vitality of Goya and Rembrandt, two ofhis models. As he himself admitted, he was poor at modelling the human form and his heads often sit uncomfortably (if at all) on the bodies that carry them. His motifs, too, are narrowly circumscribed: the same or similar rocks with cloudy contours, the same cloud like a lum- inous boulder, the same tree with its thick trunk and spindly limbs haunt a succession of drawings and paintings throughout his career. None the less, his cross-hatched and chevron lines build up intriguing textures like sooty lint. And even if the emblems are repeated, their power is intensified by repetition. Just as a book of poems can extend the significance of one poem's imagery through its interplay with other poems, so Redon in his litho- graphic albums pioneered the graphic equivalent: each single motif, repeated in this context, grew more potent and mysterious. This device was developed by the Surrealists, notably in Max Ernst's lithographic albums and in Max Klinger's incomparable sequence The Glove. It is this intensity that has sustained the interest in Redon, among both critics and the public, while the reputation of the other Decadents, his contemporaries Bresdin, Moreau, and Puvis de Chavannes, has plummeted. He himself claimed to have "opened asmall window on to mystery". And while we may not share his credulous obeisance towards "mystery", there is some truth in Redon's claim. He has supplied lasting emblems of the uncanny, unforgettable images of obsession, enslavement and psychological paralysis of the kind that dreams reveal and that consciousness forgets with a shudder. The bright colours of Redon's later painting seem almost unbearably intense compared with the darkness of his graphic work. It is as though the small window he had opened has been shut and the walls which enclosed him had swung open on to a landscape of vivid pigments. They are radiant, but they lack the brooding originality of his earlier, inward visions. But they, and that brooding originality, show how right Redon was to have faith in dreams as a legitimate subject for art.