The Irish-Canadian author Emma Donoghue wrote contemporary fiction about sexual identity before switching to the feisty voice of an eighteenth-century London prostitute in the acclaimed novel Slammerkin. In this new offering, longlisted for the Man Booker, she changes tack again.

Room – the lack of article signifies much – is the only world five-year-old Jack has ever known. The space concerned is eleven feet square. He shares it with Ma, but also with Bed and Table, Rocker and Shelf. The only visitor is Old Nick: hated, feared, to