Laura Thompson's previous subject was Nancy Mitford, whose biography had already been ably written by Selina Hastings, and she made a decent go of it - even if it wasn't exactly crammed with revelations, and even if her style was, at times, on the toothache-inducing side of syrupy (Nancy herself would have honked like a drain at its worst excesses). So what is the restless biographer to do? Go back, that's what: try someone who was last 'done' a couple of decades ago. Meanwhile, all the meatiest names have already been done. A few writers die every year, which is helpful, but not all of them, alas, are worthy of their own book. If you read lots of literary biographies, as I do, you can't help but feel that the available pool of subjects is distinctly puddle-sized.