Its greatest pleasures are its details, which are as richly imagined as in the best adult science fiction. But like much of the new wave of children’s SF – and perhaps precisely because of his audience – Reeve also does many other things very well. There’s a lot of humour here, as when a list of old Earth languages is thought to include Klingon and “Ancient Geek”. Above all, he delivers an unflaggingly propulsive narrative that is never derailed by world-building. Rather, it rattles along like an interstellar express, leaving you eager for the next thrilling ride.