The power and passion of this nude fired me at a critical moment when I was getting to grips with a central and tricky theme of the book. But why? I won't keep you guessing. Degas's study of a young woman seems absolutely direct: an observation inflamed by desire. But it is also a homage to Michelangelo. Her pose is closely modelled on male nudes that Michelangelo did in competition with Leonardo da Vinci in Florence in 1504-6.
The Degas drawing translates Michelangelo's male bodies into a female image. And, to be blunt, that helped unlock my own appreciation of the erotic power of the youthful art of Michelangelo. I refuse to see the "nude" as being different in some elevated way from the "naked". Eroticism and intimacy are inherent in any strong depiction of the human body, but writing about the nude is tricky. You can't really do it unless you acknowledge your own feelings – which, I suppose, is the reason the pleasant fiction of the sexless nude was invented by 18th-century critics: to avoid embarrassment.
The drawing by Degas helped me recognise the sexual nature of Michelangelo's art. So the National Gallery helped me with the book, just as it has helped me to learn about great art, and it will mean a lot to be speaking here about The Lost Battles on 15 November. I promise not to be too embarrassing, either about nudes or about my love of the gallery.
• Jonathan Jones will be the speaker at the National Gallery's lunchtime talk on Monday 15 November from 1-1.45pm.
A little-known Yorkshire painter has become the talk of London's art world after drawing record crowds to an exhibition at the National Gallery.
Visitors have queued in the first fortnight to see Clive Head's modest sideshow to the gallery's current major display of Canalettos – a linked display commissioned to give a contemporary twist to the great Venetian's work.
Based in Scarborough, where he headed the art department at York University's local campus, the interest in 45-year-old Head's three large "cityscapes" has astonished gallery staff.
"He has broken the record for a contemporary artist in Room One [the gallery's small temporary exhibition space]," said Colin Wiggins, the National Gallery's chief curator.
"But it is the time which people are spending in front of his pictures that is really impressive. The room is always thronged. We are busy, busy. The statistics speak for themselves – 7,300 visitors in the first week, 9,300 in the second – but the level of interest defies that sort of analysis by numbers.
"Head's work seems to be the kind of painting that people really love. There's a sense of delight in discovering that it is alive and well, alongside what might be seen as 'Turner Prize art" and the work of more highly-publicised artists."
Head is by no means a secret in the art world, with his paintings fetching up to £160,000 and appearing regularly in West End galleries, but his name has seldom made major headlines. His career was knocked back by a muscular condition five years ago, but he recovered and developed a style variously described as Hyper or Cubist Realism.
"I rate him as the first artist to create a visual language of the 21st century," said Michael Paraskos, an art critic and former colleague of Head's, whose monograph on the artist came out this year.
"His technique is complex, detailed and apparently realistic – but only apparently. Just look closely, as all these visitors are doing, at what is going on."
Head, who discusses his work with Paraskos at the National Gallery on Monday, said that he was warmed and intrigued by the interest – to the extent that he spent time this week watching people watch the paintings.
"There is an appreciation of technique – you know the sort of thing: 'This chap knows how to paint,' but what really seems to appeal is the gradual discovery of how much is happening in the paintings. It's the spatial complexity, the sense that different times and places are contained within initially seems a straightforward, hyper-realistic picture."
Head's guest stint in Trafalgar Square followed a visit by Wiggins to the Marlborough Fine Art gallery two years ago, when negotiations for the Canaletto exhibition were in progress.
Wiggins said: "I went there to have a look at their summer show, which features work by all their artists. I saw the effect of Head's work. People were mesmerised."
Wiggins and his colleagues sensed a connection with Canaletto's own spatial mastery and intrigue, and decided to offer room for three paintings, which will be followed in December and January by a second guest exhibition by another "cityscape" master, Ben Johnson.
"Contemporary work in the National Gallery is a very delicate matter. When artists are exhibiting alongside Rembrandt and Michelangelo, there is a clear risk that it can end up looking stupid," said Wiggins. "That is certainly not the case here. We have a very fine example of contemporary and classical art which connect."
Head works mainly in London, and the trio of paintings are of Haymarket, seen through almost 300 degrees, a cafe in South Kensington, both inside and out, and a stairway in Victoria Underground station, which gives a powerful sense of taking in different views.
Head said that living in Yorkshire had allowed him detachment, something which has also marked the drama of Scarborough's best-known resident, Sir Alan Ayckbourn. Head said: "It's helpful to keep a distance from fads and fashions. You are more likely to find your own path.
"Scarborough is a very level-headed place. People know who I am but they have other things to get on with. I get stopped in the street more often in Mayfair than I do in Scarborough."
Head's agent at Marlborough, Armin Bienger, said that the reaction in Room One had not surprised him, after previous experience in the West End. He said: "Every time I have showed Clive's work, I have had this experience. It is like a magnet. People become more and more fascinated, the more they look.
"This is not remotely like photography, nor like traditional photorealism. The landscapes exist in the real world, for example at the Cottage Delight cafe near the Natural History Museum, but they are not as Clive shows them. He has found a way of creating an image which takes us through time."
Leggy birds with beaks and wings fashioned as graceful geometries are typical of Breon O'Casey's sculpture. So too buxom Earth Mothers, primitive nudes with vast hips, cast in mottled bronze. It's no surprise to learn that this son of the Irish playwright Sean O'Casey was assistant and friend to Barbara Hepworth. Now in his 80s, he's one of the last surviving members of the St Ives School. His first love, though, ispainting. Canvases feature classic abstract subjects from nudes to landscapes, in the manner of the gods of modern art, Picasso and Mattisse. Birds and fish become teardrop shapes in earthy hues, a view of a Venetian canal is transformed into mirrored half-moons while a reclining nude becomes a satisfying series of ripe ovals, half-moons and circles.
Somerset House, WC1, to 30 Jan
David Gledhill, Corin Sworn, Manchester
David Gledhill's Doctor Munscheld photo-realist paintings are meticulous renditions taken from a 1950s photo album picked up from a Frankfurt flea market. The paintings' chilling air of displaced nostalgia derives from the seeming incompatibility of dead ordinary family snaps and the artfulness of Gledhill's painterly dedication. Corin Sworn's Endless Renovation visuals are a run of projected slides salvaged from a skip. Sworn adds a voiceover monologue that transforms them into a plaintive meditation on the unstoppable passage of time.
Castlefield Gallery, to 19 Dec
Contemporary Eye, Chichester
Using craft techniques in contemporary art has gone from being a radical bit of revisionism to par for the course in recent years. The subversive works here represent both newbies and artists at the vanguard of the trend. Laura Ford's Chintz Girl riffs on the oppressive limits of the mantelpiece while Debbie Lawson turns home decor into a site for imaginative escape, with her Turkish rug sprouting fabric flowers. There are stuffed animals aplenty in Nina Saunders's amalgams of taxidermy forest creatures and elaborately upholstered furniture, but no show of this kind would be complete without Grayson Perry. Here he switches ceramics for an anti-war tapestry, depicting guns, helicopters, Osama Bin Laden and a priapic angry teddybear.
Pallant House Gallery, to 6 Mar
Rebecca Lennon, Liverpool
Rebecca Lennon's first solo show is a celebration of our common fallibilities titled We Are Stuck Here Together. Past work has included a pigeon video, and a sound collage of the sole word Satisfaction sampled from 38 cover versions of the Rolling Stones classic. Lennon's gift lies in knowing precisely what to lift from the most seemingly arbitrary of sources. The current show includes such ready-made gems as a film clip of a man acting out a sleep disorder and a painting apparently offered to a debt collecting agency in part payment for a debt. And all these things are posited in a spirit of deadpan earnestness as documents of rare cultural import. And, indeed, they could well be just that.
Ceri Hand Gallery, to 28 Nov
Rirkrit Tiravanija, London
Rirkrit Tiravanija's people-friendly projects included cooking Thai curry for gallery-goers and transforming a white cube into a makeshift studio for bands to practice in. In recent years, however, his work's got less utopian and more political. Here he explores the business of art in two very different worlds: London and Thailand. An eight-hour video portrait shot in continuous close-up records the working day of an aged Thai man, the artist's model. It's an endurance test, like one of Andy Warhol's early films. Meanwhile, slides show Tiravanija's London gallerist at Speaker's Corner, using a blackboard to announce daily tasks like emailing collectors.
Pilar Corrias, W1, to 1 Dec
Joan Ainley, Castle Donington
Joan Ainley's new set of collaged prints, The Eye Of Time Rewrites History, is the second in her ongoing series Portraits Without Pictures, Sound Without Noise. Ainley's work tends towards the poetic and enigmatic, more obliquely evocative than clearly descriptive. She has a distinct taste for the conjuring of objects that have a unique drawing power but which frustrate any attempt at prosaic interpretation. She goes in for empty frames and blank mirrors, and contraptions that hint at the potential for creative sound rather than producing actual audible music. The raw materials for her collages were sourced from old catalogue illustrations for barbershop supplies, lab equipment and Army & Navy stores. The antiquated engravings excavate the surreal formalities of barely obscured collective memories of railway station clocks, starched collars and cutthroat razors.
Tarpey Gallery, to 4 Dec
Pioneering Painters: The Glasgow Boys 1880-1900, London
Until the Glasgow Boys came along, Scotland's fin-de-siècle painting was a staid, sombre affair. At the end of the 19th century they looked to innovators across the water, introducing the hot colours of southern France, the dappled light of impressionism and the social span of French realism in their experimental painting. Taking their materials out of the studio and into the countryside to work in the fresh air, the group gave rural life in the chilly north an image makeover. Included in this survey are such delights as James Guthrie's depictions of age and youth, his little girl herding geese, and Arthur Melville's vision of the Trossachs as a fiery autumnal haze. The highlight though is EA Hornel and George Henry's The Druids: a cavalcade of Celtic priests, resplendent in scarlet, aquamarine and gold leaf against a winter backdrop.
Royal Academy Of Art, W1, Sat to 23 Jan
Jorn Ebner, Newcastle upon Tyne
Jorn Ebner's graphic digital mischief tends to fluctuate between a utopian heaven and a dystopian hell in an atmosphere of distinctly spaced-out bewilderment. The overall title of his recent work Uncertainty Underneath Immense Skies is taken from Jack Kerouac's On The Road. Ebner's computer-enabled protagonists might prance about amidst the flower-power daisies and appear to go in for elaborate variations on a theme of free love, but there's an ever-present undertone of deadpan irony. In one inkjet print titled Richard Brautigan Pounding At The Gates Of American Literature, the trouserless poet stands forlornly above a prone nude girl with his erection pointing to a sky infected by a multicoloured psychedelic plague.