The making of large imaginary worlds, whole kingdoms with their landscape, their peoples and their politics (usually medieval, these, with barons, and kings good and bad) is a recurrent form of story. Cart and Cwidder is just such a story. North and south are at loggerheads; vile tyranny crushes the south. Clennan, the travelling singer with his cart, journeys between the two. He and his children are just entertainers, busking in one town after another for their bread—or so the children think, but Clennan is not only what he seems.

A fantasy adventure, especially one that culminates in the gathering of armies, epic fashion, invites comparison with [J.R.R. Tolkien's] The Hobbit; but this is not another derivative book, for Diana Wynne Jones has a subject of her own to involve us in. Not the eternal war of good and evil, as in Tolkien, but the...