The lice even infested their eyelashes. So writes Anne Berest in her roman vrai bestseller, The Postcard, describing the camp conditions her grand-aunt and grand-uncle endured on their way to their deaths in Auschwitz, followed by their parents. It is the incidental detail – the image of parasites crawling in the eyes of the doomed – that can haunt a mind all too familiar with the facts of the Nazis’ barbarity. Jacques, the younger of the siblings, was 16 when he entered the gas chamber to join six million Jews murdered in the Holocaust. Noémie, an aspiring novelist aged 19,...