Old Man Goya, by Julia Blackburn

Dea Birkett acclaims a bold portrait that refuses to draw the line between fact and fiction

This is a book about two people, their family, and their worlds, separated by almost 200 years. One is the author, the other her subject. Julia Blackburn (21st-century British writer) and Francisco de Goya (early 19th-century Spanish painter) cohabit on almost every page.

The hard bones of Goya's late life are these: at 47, following a severe illness, he went profoundly deaf, and it is here that Blackburn joins him. From this silence, she details the royal paintings and many etchings he made over his last 35 years until his death in 1828. But this is where concrete evidence ends. The rest is not his history, but her imagination.

With the help of a pair of earplugs, Blackburn writes about the old painter's world without sound: screaming faces with no voice emerging, barking dogs baring soundless jaws, the silence of a frenzied crowd. What Goya sees, Blackburn gazes upon. Where Goya goes, Blackburn follows. Arm in arm, they walk along the Street of Little Moles in Bordeaux, where the old painter used to spot prostitutes. "We sat in a little café on the edge of the square and drank mint tea from glasses," writes Blackburn, as if recalling an encounter with a friend.

Even what Goya eats, Blackburn sups on. "At an inn in the town of Tolosa I would have Goya eating the same food that I was served there," she writes. "A bright red soup, followed by an omelette cooked with dried cod and then pieces of ox cheek with little patches of black hair still clinging to the seared flesh."

So complete is the joint script, occasionally we're confused as to whether we're reading about the author's or her subject's life. "There was a big storm last night," opens one chapter, and I wonder if the sky broke open in 1816 or 1998. This is not the first time Blackburn has confused us. In The Emperor's Last Island, covering Napoleon's last years on St Helena, and Daisy Bates in the Desert, about the maverick Irish missionary to the Aborigines, she took the boundaries between fiction, biography, history and memoir, and, like a true adventurer, irreverently ignored them. We had never read anything like it before.

By the time we reach Old Man Goya, however, boundary crossing is not so new. We have grown accustomed to this confusion of form. At first we were disturbed when we learnt that the opening of Bruce Chatwin's In Patagonia was fabrication: "In my grandmother's dining-room there was a glass-fronted cabinet and in the cabinet a piece of skin..." There was no cabinet and no skin. Now, we are not shocked at this blending of fact and fiction, and do not demand each to be clearly marked. So when Blackburn's opening lines echo Chatwin's – "When I was a child there was a paperback edition of his [Goya's] etchings tucked small and unobtrusive in the bookcase" – we no longer care about the veracity. We only care if the story works well.

Old Man Goya not only works well. It also openly reveals this melding of reality and fantasy. On every page, paralleling the life, is the process by which it is made. The writer's internal journey is blatantly outed, stripping the flesh from the skeleton of biography. The plentiful openings of "I imagine Goya", "I think of him", "I am sure he liked", all testify to the fabrication that any portrait of a life must be. Blackburn describes incidents in Goya's life, even his most intimate moments ("warming his cold feet between her thighs"), with the confidence of someone who knows the old man well. Many assertions are unsubstantiated by anything other than intuition. Yet we trust them. We believe what Blackburn writes is as near the truth as a story can be.

All stories – fact or fiction – are made up. Few writers are as brave as Blackburn, and as prepared to admit that. Few writers are as able to show us how that process of make-believe works.