Wasn't it unusual reading matter for a squaddie sitting in a Sapper barracks? "I'd heard it was a book that only six people in the world had managed to read. But I thought it was wonderful – it was funny, the language was magical It took over my life for a while". Had he visualised the narrative through an artist's eyes? "I thought of doing some etchings. But then I realised that nothing is described in Ulysses, there's no visual sense in the whole book."And yet I had an image of the book in my head – somehow Joyce had put it there without any of the usual textual devices.

Just as everyone has the same picture of Leopold Bloom in their heads, although he's never described." And yes, Hamilton's drawing of Joyce's comic Everyman is instantly recognisable – dapper, waistcoated and formal but with a sensual, Romantic melancholy about his Mediterranean-Jewish features and baggy black trousers.Hamilton's illustrations – 109 preliminary drawings, studies and reworkings – amount to a brief history of artistic technique One shows Bloom lying in the bath. Its inspiration is the last paragraph of Chapter Five: "He foresaw his pale body reclined in it at full, naked, in a womb of warmth, oiled by scented melting soap, softly laved..." Look at Hamilton's earliest ink-on-paper drawings of the scene, and it is clear that he was then wrestling, to an almost comical degree, with the description of Bloom's penis as "the limp father of thousands, a languid, floating flower". His 1947 drawing shows a side-view of Bloom au bain; bizarrely circling his head, on the margins of the drawing, are a score of try-out sketches of various penis-shaped flora – tulips, canna lilies, red-hot pokers. When he returned to the image in 1983, "I saw that the key words were 'He foresaw his frail body', and that the image had to be Bloom looking down at himself".

The result is a completely different, stylised pencil-and-watercolour illustration that foreshortens Bloom's squat body, with a nod to the figure of Jesus in Mantegna's The Dead Christ. Hamilton relishes the minutiae of Joyce studies, and the games played by even its most serious practitioners. "I had the privilege of meeting Richard Ellman [the great Joyce biographer] when I lived near Oxford, and then he came to dinner. He looked at these drawings and said, 'I see you've circumcised Bloom' I said 'Yes, of course' He said, 'But Bloom wasn't circumcised'. I went back and read the book, but couldn't find any such suggestion, so I wrote him a note saying, 'I can't find it Tell me' He finally told me the chapter and the line. It's just one of two moments in the book where Jewish observances aren't kept..."Looking round this exhibition, one marvels at Hamilton's obsessive struggle with the great book over six decades. He started many of the drawings in the late 1940s, abandoned them for technical reasons, came back to them 20 years later, stopped again, restarted in the late 1970s, and applied the finishing touches in the last few years.

A yawning gulf separates his versions of Bronze by Gold, depicting the two flirty barmaids from Chapter 11, flame-haired Miss Douce and blonde Miss Kennedy. In 1949, it was a washy concoction of greys and magentas; by 1985, the women could be straight out of The Simpsons.The chapter that had most effect on him was The Oxen of the Sun, the famous Chapter 14 in which (see above) a baby is born and the English language gradually evolves. "This was most influential because of the mixing of styles," said Hamilton. "It moves through the growth of language, so the illustration had to be about the birth of imagery." And sure enough, he does the impossible and tries to chart the evolution of painting in depicting a crowd of drinkers in a waiting-room.