Memoirs of private life (and most recent narrative non-fiction is of this kind) aren’t easily checkable in that way, yet are assumed to have reliable narrators. The slogan is seductive, but it’s equally arguable that all the best stories (Aesop, Homer, Chaucer, Shakespeare, Grimm, Tolstoy) are made up. Even if they’re not honest, they’re true.”All the best stories are true” ran the logo to a non-fiction award a few years ago. It is a tricksy preface, yet the texture of the stories themselves is old-fashioned, intimate, dependable They seem honest. The man is fiction, but the mask is real.” This preface is signed “PT”, which could be a confession of authorship but might stand for “prick-tease” or even “post-modern trick”. It is the writer’s privilege to keep some facades intact and use his own face in the masquerade It was the only area in which I took no liberties. Whether any, some or all of the events described actually happened or not, Theroux isn’t telling.

Or rather he is telling, story-telling, asking us to enjoy his book for its own sake without worrying overmuch whether it’s true This isn’t something every reader will feel able to do. Thomas Hardy once said that there was an “infinite mischief” in “the mixing of fact and fiction in unknown proportions”.Certainly, Theroux is being mischievous when he writes in his preface: “As for the other I, the Paul Theroux who looks like me – he is just a fellow wearing a mask. But the main character is a novelist called Paul Theroux, whose background bears a striking resemblance to that of the real Paul Theroux, also a novelist. Other characters in the book include Anthony Burgess and Queen Elizabeth II, as well as some whose real-life lineaments are recognisable but whose names have been changed.

Certainly there’d be a sense of outrage if these writers had secretly been enjoying good health.Away from hospital, it’s possible to be more playful. When Paul Theroux published a book with the title My Other Life he called it a novel just as he had his earlier My Secret History. Perhaps illness and death are special cases, requiring solemn observation of category lines. The claims they make on us depend on our conviction that their ordeals really did happen as described. There have been columns of this kind, too – Oscar Moore on having Aids, Ruth Picardie and John Diamond on having cancer. When Harold Brodkey wrote a piece for the New Yorker that began “I have Aids”, readers were moved; they’d not have been moved if it had turned out Brodkey was making this up, though they knew him to be a writer of fiction.