The novel has been treated both as a war novel and an anti-war novel. In her 2004 interview with critic Rob Nixon, Barker describes her conceptualisation of that boundary:
It's not an antiwar book in the very simple sense that I was afraid it might seem at the beginning. Not that it isn't an antiwar book: it is. But you can't set up things like the Somme or Passchendaele and use them as an Aunt Sally, because nobody thinks the Somme and Passchendaele were a good idea. So in a sense what we appear to be arguing about is never ever going to be what they [the characters] are actually arguing about, which is a much deeper question of honor, I think. "Honor" is another old-fashioned word like "heroism," but it's very much a key word in the book.
Moreover, because of the novel's strict adherence to history, critic Greg Harris describes the novel pushing the boundaries between historical fiction and non-fiction. In her study of the novel, Karin Westman describes the act of writing historical fiction as "a challenge" for Barker. Westman notes that Barker, at times, made deliberate choices not to preserve realism, when, for example, she omits the kinds of language and humour used by soldiers during the period. In some interviews, Barker directly challenges the characterisation of the novel as an "historical novel," suggesting that the First World War stands in for other wars and allows her to represent more unspecific war-related themes.