In this, and upstairs in the three floor-related pieces, you find the real importance of Judd He was the artist who defined and informed values of space. There are woodcuts, which might surprise some people, but they suit Don. When you make a woodcut you're removing part of the block - in a sense removing the space. So much so that it took me a couple of years to really understand it. It was his retrospective at the Whitney in 1967 that was the epiphany for me. This show in Oxford gives the full range of Don's work. It's a beautifully installed selection, ranging from prints and furniture to large objects.

I first met Donald Judd in the late Sixties but I'd already seen his work in 1965 It was just so different from anything else. In his postscript to the catalogue, Craig-Martin lam e nts various works he couldn't borrow by, among others, Piet Mondrian, Bellini, Pollock and Antonin Artaud, who made some of the fiercest and most compelling drawings of the past half-century.But this is not to quibble; after all, when has Cy Twombly ever before been shown with Perugino, Beuys with Blake, Judd with Mantegna? What they share is not so much drawing, a style or a subject, as the persistence of the imagination.. Each drawing represents the head in terms of the skull beneath the skin, and the grouping is an essay in mortality. A De Kooning standing figure, Trembling Woman, from the early 1960s, isplaced beside the cursory arabesques of a Turner aide memoire.

Turner's private shorthand study at first sight looks like nothing so much as a scrap on which he tried out a new pen-nib, but reveals itself to be a compositional note for a vast history painting, while the De Kooning, drawn with the edge of a stick of charcoal, belongs to a series of figures the artist made either with his eyes closed or with his left hand and which were the precursors to his monumental Clam-Diggers.Three skull-like heads hang together: one of Picasso's last drawings, with haggard, blank-eyed stare; Jean-Michel Basquiat's raw, tangled line describing an emblematic, robotic head; and a Hans Arp titled Danger of Death, a twitching apparition of a skull emerging as though by chance from the distracted wandering of his pencil. But it is Craig-Martin's o r chestrations to which the viewer returns again and again. One telling ensemble includes a Franz Kline collision of black swipes, Gaudier-Brzeska's portrait of Ezra Pound, a Cozens tree, three figures by Romney, a Corot and a 19th-century Japanese ink dra wing - a group summarising almost all there is to say about the possibilities presented by a blank sheet of paper and a brush dipped in black ink.On other occasions, groupings are made in terms of a recurrent motif: Robert Smithson's Spiralling Jetty sensibly hangs near a carved neolithic spiral and Damien Hirst's furious ballpoint beautiful accelerating whirlpool drawing (with psychotic activity). Louise Bourgeois and Miro were made for each other, while Rembrandt and Philip Guston make an alarming pair. Rembrandt's Jael Killing Sisera shows Jael about to bash Sisera's brains in with a mallet. Guston's drawing, rendered in his late, stumblebum style, shows the aftermath of some terrible, but crazy, cartoonish scene.

There's something atavistic about both images: Jael's raised club and Guston's length of timber with a nail stuck through it are rendered with an equivalent kind of dumb brutality. Correspondences make the show, and those who complain that artists don't or can't draw any more are in for a shock.It is telling that what might be regarded as essentially minor works, or drawings that artists made purely for themselves, have as much potency as pieces made for public consumption. What all three drawings share is, perhaps, a kind of fixated intensity, evidenced as an involuntary muscular twitching: what Michaux describes as "a prodigious vibration, multiple, delicate, polymorphous, appalling, and which will apparently ne ver stop".One finds oneself patrolling back and forth to make one's own comparisons between Cozens and Arp, between Andre Masson's Sadean orgy and Luca Cambiaso's Flagellation, between an Egyptian papyrus and a scene on a classical pot. Auerbach's muc h erased and reworked drawing delineates a human head in a sequence of hurried swerves, convulsive jerks and twists, while in Della Bella's delicate, intricate study the voluminous plumes on the horsemen's helmets are made up of tiny whorls and jagged aft ershocks. These serendipitous affinities sharpen our awareness of the essential differences between the artist's sensibilities and intentions. Elsewhere, an idea about mapping three-dimensional space provides the continuity between a Constable study the artist has gridded-up for transfer to a canvas and Henry C Beck's roughed-out diagram for the London Underground tube map.One of Henri Michaux's "Mescalinean" drawings, a seismic trail of faint stutters and tremors, hangs between a recent portrait drawing by Frank Auerbach and a study of three horsemen by the 17th-century Italian artist Stephano Della Bella.

Ingres sits beside Agnes Martin, the parallel lines of Martin's abstraction echoed in the folds of Ingres's sitter's dress and in the lines we see her drawing in a sketchbook. Giacometti's tree and Whistler's street scene are bought together because of their compositional similarity, as are Vasari and Rachel Whiteread, a Malevich Suprematist drawing and a Philip Guston head, a Delacroix and an Arshile Gorky. He has hung the show not as an art historian might, but as an artist, and rather than arranging works chronologicall y he presents us with a barrage of startling confrontations. As its title suggests, the exhibition focuses on drawings whose essential constituent is the use of line rather than mass or tonal gradation: it is a line unravelling and turning back on itselfthrough space and time, looping from Rajasthan to the Netherlands, from Stonehenge to New York City, from Altdorfer's fantastical Bavaria to Van Gogh's asylum at St Remy, tracing a web of continuities, and disjunctions across cultures and historical epochs.A Barnett Newman hangs beside a Degas, linked only by the curator's quixotic gesture and the way in which the two artists allow ink and charcoal to graze the paper (in the catalogue, Newman's single vertical zip is twinned with a Michelangelo study of a human leg).