What are the most important ideas in The Wizard of Earthsea?

I think central to this excellent fantasy novel is the
gradual transformation and process of maturity of Ged, who starts off in the novel as a
wizard with tremendous ability, to being a mature adult who is able to control and use
his power wisely. In many ways, this novel is a coming-of-age story, where we follow
Ged's progress from being a rather arrogant and vain individual who is eager to show off
his power for the wrong reasons, to the mature archmage that he becomes when he is able
to face and confront his own mistakes and take ownership of
them.

We see this most clearly in the way that he unleashes
the devastating shadow upon Earthsea over a silly argument with Jasper about who is the
most powerful magician. Personal pride and arrogance results in Ged setting a force of
evil free that will torment both himself and others. However, at the same time, by the
end of the novel, we see that Ged has matured so much that he is able to choose the good
of others over his own personal benefit, such as when he does not make a deal with the
dragon to gain the name of the shadow. At the end, when he confronts the shadow, he
confronts the evil within himself. His recognition of this completes his coming of age
and shows the final step of his maturity.