Under the Sun: The Letters of Bruce Chatwin, edited by Elizabeth Chatwin and Nicholas Shakespeare

Idined with the Brauns last night among their palms, their Cordoba leathers, their aseptic marble goddesses, their bronzes of fishermen, their Louis-the Hotel-Quinze suites, their painting (of two geese with disjointed necks) by Picasso's father, their marquetry floors, their billiard table, the bird-like French patter of their black dressed ladies and the assumed upper-class accents of their men." To read Bruce Chatwin's letters is to remember that he was first and foremost a collector, of objects, of people, and of obscure academic research he could bring to a wider world. The cataloguing skills he acquired in his early days at Sotheby's stood him in good stead in his later career as a writer – as did his eye for a bargain.

These letters are full of antiquities bought and sold to keep him solvent and on the move: a Mongol suit of leather armour, an Inca head-dress, a Napoleonic camp-bed. Given the scale of his travels, he needed a brisk turnaround. His endless restlessness – exhausting for those close to him – sees him perpetually either travelling or thinking about where to go next, preferably to an exotic location that his correspondent will have to look up, like Balkh or Chitral: "I have just come back from the mountains of Aïr."

Not for Chatwin "a sense of place". What he likes – and, perhaps, his literary legacy – is a sense of disjunction, finding the alien or unexpected in a novel setting: the Russian adrift in Australia; the Welsh in Patagonia; the Italian archaeologist he meets in Vienna, voracious both in his womanising and appetite for duck with dumpling. He finds it easier to write On the Black Hill about Breconshire when in the Caribbean.

His teacher at Edinburgh University, Stuart Piggott, already writes that Chatwin "is running away from himself by travelling". The story that follows has already been well told in Nicholas Shakespeare's biography: the writing apprenticeship with The Sunday Times; the sudden compulsion to go to Patagonia for his first book; a frenetic and successful last decade brought up short by the onset of HIV-related infection and his death in 1989.

What these letters provide is Chatwin's sheer exuberant vitality on the run. Books like In Patagonia were honed down from sprawling manuscripts to a quarter of the length, the results as sparse as the architecture of the abandoned French monasteries he so admired. But in the correspondence we get a more full-blooded, motor-mouth Chatwin, riffing on architecture, sex and the origins of life even when dashing off a postcard (the postcard being his perfect vehicle; many are of objects he would like to buy).

The letters have been edited by Shakespeare and Chatwin's widow, Elizabeth, whose pithy and astute comments undercut some of her husband's wilder claims. BC: "I have bought the largest coco-de-mer I have ever seen. Beautiful and obscene. We take it to bed." EC in footnote: "Nonsense".

The story of their troubled relationship comes through more powerfully than in the biography. Elizabeth remains his confidante even in times of marital breakdown, and he is honest with her while sometimes selling a line to those he wishes to impress. As Shakespeare comments, Chatwin was a "mythomane", continually blurring the line between fact and fiction in both his books and life.

These letters are never dull; this is Chatwin at his finest, wild and unconstrained. And even his detractors could not fail to be moved by the final stages of the correspondence. As the HIV infection and accompanying mild delirium take hold, he goes into a frenzy of both letter-writing and collecting, spending a day in a wheelchair around Piccadilly buying up a Bronze Age armband and an Etruscan head for £200,000.

In one of the final letters, Michael Ignatieff writes to tell him that "those who love you – and see only the outside – see someone hunted and in breathless pursuit... I may just be expressing a friend's regret at losing you to a great wave of conviction, to some gust of certainty, that leaves me here, rooted to the spot, and you carried far away." Or as Chatwin writes about another's death: "One's hold on life is extremely tenuous."

Hugh Thomson's 'Tequila Oil: Getting Lost in Mexico' was shortlisted for the Dolman Best Travel Book Award