On 20 August 1914 Edith Cavell watched as fifty thousand German soldiers marched into Brussels. Overnight her life changed from archetypal hospital matron to the concealment and subversion of a resistance worker. Nothing in her Victorian upbringing as the vicar’s daughter in a small Norfolk village prepared her for the brutality of her final years. But this moving and elegant biography draws on the qualities of altruism, humanity and bravery that sustained her, first as a pioneering nurse and then as a war hero, and made her an inspiring figure to whom more monuments were built and tributes paid than to any other woman caught in the carnage of the First World.