Consistency is to an imaginary world as the laws of physics are to ours. As Francis Spufford puts it, in The Child that Books Built, 'all shared with Tolkien was the deep consistency that allows an imagined world to unfold from its premises solidly. Coming hard after my reading of Tolkien, she had a hard act to follow. But not modishly so: it makes sense to itself, and to the reader. The book was published at the end of the 1960s, and so is shot through with notions of yin and yang. At the end of the first book, Sparrowhawk works out that this creature does in fact have a true name: it is his own. Somehow it knows Sparrowhawk's true name. The hero of the series, Sparrowhawk, is a proud, difficult boy from a mountainous island famous only for its pirates, goat-herds and wizards in a clandestine contest at the wizards' school between himself and the arrogant snob (yes, there's one in Potter, too), he reaches into the world of death and unleashes a nameless dark force, a clot of pure evil and malice, that pursues him to the ends of the earth.

The purpose of the wizards' school in Earthsea is to teach one how to use magic without upsetting the balance of the world. There are competing magical forces: not so much between light and darkness, as between the wise and sensible use of magic - and darkness. There are dragons, for whom the ancient tongue is native, but they are not to be trusted: while incapable of lying, they have different conceptions of truth.

To know someone's true name is to have power over him or her it is vouchsafed only to those whom one trusts utterly.

Earthsea is an imaginary archipelago, the traditional pre-industrial world of children's fantasy literature, but governed by a supremely compelling and simple idea: there is an ancient language of creation, and anyone who has the gift of sorcery and who can speak that language, in which things are given their true, as opposed to arbitrarily phonemic names, can master their physical presence.

The farthest shore ursula le guin