I’m rearranging my books. Rather than having everything muddled together I want biography and autobiography in one room and fiction in another. Sounds straightforward enough, but I’ve already come unstuck.

What should I do about fictional biography (like Virginia Woolf’s Flush), biographical fiction (like Robert Graves’s I, Claudius), fictional autobiography (Gertrude Stein’s The Autobiography of Alice B Toklas), autobiographical fiction (Sylvia Plath’s The Bell Jar), and that new-fangled thing called autofiction, which the bookshops file under fiction but I read entirely as auto? I need a set of subgenres, and will label the shelves accordingly.

But what about James Frey’s A Million Little Pieces? Autobiography or fiction? A Million Little Pieces, published in 2003, is the story of how Frey washed up in a rehabilitation centre suffering from alcoholism and drug-addiction. He had been an alcoholic since he was thirteen; he then discovered crystal meth and, aged twenty-three, reached rock-bottom. He describes crashing into a police car while high, resisting arrest, serving a three-month jail sentence and being a wanted man in three states.

Selected for Oprah’s Book Club in 2005, A Million Little Pieces outsold any book that Oprah had ever plugged. It was the number one paperback non-fiction book on the New York Times bestseller list and a number one seller on Amazon, which is not bad for a writer whose