When I first read the Earthsea cycle, I was about thirteen - which was far too young to be able to appreciate LeGuin's writing properly. I've heard people call her Earthsea series children's books, and I don't understand it. At thirteen, what captivated me was the flowing writing, and the beautiful world of Earthsea - but I didn't understand the plot, not really. Both 'The Farthest Shore' and 'Tehanu' were completely beyond me at that age.
In other words - don't read these books until you are at least seventeen, and can understand a bit more what LeGuin is writing about. Loss, death, powers that lurk, unknown and unknowable, in the darkness, pride, fear, all these things make up the Earthsea series. But other things as well: love, and friendship, self-sacrifice, trust, and above all a kind of joy, a wrenching painful joy, a hopeful joy despite all the bad things that have come with it.
Now, I doubt most people will understand a single word of what I'm on about - but if you've read The Lord of the Rings, you'll know exactly what I mean. Its a kind of release to read these books, an escape and a refuge. LeGuin has written not simply a story but a myth, in the same way that Tolkien did. And like Tolkien, and Patricia McKillip, and (occasionally) Marion Zimmer Bradley, what makes her tales truly great is not what she says, but how she says it. The Earthsea books should be read out loud, and when you do they sound like music.