India, April 26 -- The abiding memory of my teenage years is reading Agatha Christie. On holiday from school, I would spend hot summer afternoons stretched out on a sofa under a furiously whirling fan, absorbed in her murder mysteries. It was mainly Hercule Poirot and Miss Marple. Of Tommy and Tuppence Beresford, Parker Pyne and Harley Quin, I knew nothing. But I was dimly aware that she had written 66 detective novels, which sold over 2 billion copies, an amount surpassed only by the Bible and Shakespeare and translated into over a hundred languages.

However, of Agatha Christie herself, I knew precious little. That has now been filled in by Lucy Worsley's fascinating biography, which I chanced upon recently. It is rightly subtitled A Ve...