Text as illustration

You can begin where Alasdair Gray begins: with illustration. "Cover artwork by Alasdair Gray" declares the inside back cover of Lanark, for its jacket is covered with the author's own pen-and-ink drawings. These illuminate the book's copiousness and its allegorical purposes. Lanark is made from two stories, the one enfolding the other. A partly autobiographical Bildungsroman tells the story of Duncan Thaw, a would-be artist growing up, like Gray, in Glasgow in the 1940s and 50s. This is contained within a fantastic, anti-realist narrative of what seems to be a visit to Hell by a man named Lanark, who appears to be Thaw after his death; Hell is a city much like Glasgow, now renamed Unthank.

Gray's cover illustration catches the mix of realism and allegory. The doleful old man pictured in a cap, for instance, is surely Duncan Thaw's father, made lonely by the death of his wife and sadder still by his son's endless reserves of truculence. This is humane "realism". Yet angels and dragons disport themselves among these weak humans. A naked, muscular woman, holding aloft the light of the sun, rises from what you know are the waters of the River Clyde. For the background to the fiction is always Glasgow, and here its shipyard cranes and bridges, its cemetery and its baleful memorial to John Knox crowd into the gaps of the picture.

Lanark is subtitled "A Life in Four Books", and each of those books has an elaborately designed title page. Gray takes us back to the renaissance tradition (revived by one of his heroes, William Blake) of opening the reader's route into a text through an allegorical illustration. Ambitious works - the King James Bible, Ben Jonson's writings, Robert Burton's Anatomy of Melancholy - laid out their topics in emblematic form. (The final book of Lanark has a title page parodying just such a 17th-century book, Thomas Hobbes's Leviathan.) The inventiveness of the author was, you should see, being put to the service of some larger purpose. Readers who had been educated to recognise the visual emblems of abstract ideas would know in advance how these were being brought to life in the text.

You enter Lanark via a title page that trumpets its allegorical design. Five female figures are symmetrically arranged, their significance announced with antique Latin labels. At the top of the page, Fama Bona and Fama Mala blow their horns in loud contest: Good versus Bad Renown. (In the novel, Thaw struggles to become known as an artist, only to find that he becomes notorious in the Scottish press as a "mad painter".) At the centre, like a buxom Amazon, the armoured figure of Magistra Vitae (Mistress of Life) holds aloft a globe thronged with mythical creatures, treading under her feet the skeleton Mors and the dozing old man Oblivio. (Vitality is a feminine principle in the novel, and Thaw and Lanark perplexedly chase the women who seem to promise Life.) She is flanked by the crone Experientia and the naked maiden Veritas, the two kinds of knowledge (Experience and Truth) at the opposite ends of life.

A few novelists have done this. In their original monthly parts, Dickens's novels had minutely illustrated covers, surrounding the words of the title with not only characters but also symbolic figures from the narratives to follow. They are sadly absent from most modern paperback editions. Dickens's illustrations were created by others: George Cruikshank and Hablot Browne. Gray's are his own, and, in an age in which such emblematic illustration is a foreign convention, sometimes convey the suspicion of an author's private joke. Such illustration measures the author's presence, extracting what most matters. Their crowded minutiae are fitting for such a capacious work of fiction.

Fitting also because of the story at the novel's heart. The book's cover recalls a rare genre of painting in which Gray has himself specialised, and to which his alter ego Duncan Thaw dedicates himself: the mural. In the novel's central chapters, Thaw paints a version of the creation story as rendered in Genesis on the walls and ceiling of a Presbyterian chapel. Gray himself painted a huge biblical mural in Greenhead parish church that, like Thaw's, was too ambitious quite to be completed. It was destroyed during urban "redevelopment" in the 1960s (Unthank is hellish partly by dint of being subject to such nightmarish schemes of demolition and reconstruction). Only a few photographs of it survive. And this novel, which wonderfully recreates, in word pictures, Gray's vision of creation: text as illustration.

· John Mullan is professor of English at University College London. Join him and Alasdair Gray to discuss Lanark at the Newsroom, 60 Farringdon Road, London EC1 on November 22. To reserve a ticket (£8) call 020 7886 9281 or email [e-mail]