Imagine you’re a biographer and you’re attending one of those literary parties which, even in these straightened times, speckle December like a light falling of snow. You find yourself in conversation with a novelist/a poet/someone who simply turned up with a friend and is wondering how soon they can leave without looking rude.  Your inter-locutor asks you politely ‘who are you working on?’ and you tell them. They may have heard of your putative subject, or they may not have a clue who you are talking about.  But their next question will always be the same: ‘have you got their letters?’

Letters, you see, are considered to be the purest source material that a biographer can access.  With your subject’s letters, so the thinking goes, you’ve got a short cut to their very essence.  For what are letters but bulletins from the front line of the psyche?  Forget the