So Ursula Le Guin (perhaps my favorite author of all) has won the Nebula again, for Powers, and a commenter on my post about that asked which Le Guin would be a good one to start with. My husband and I talked about this on our way to work (he is also a fiercly loyal fan) and came up with two suggestions (if you have your own recommendation, please leave a comment!)
First would have to be A Wizard of Earthsea. This is as important a YA fantasy as they come, I think, the first book I know of to explore what happens when a boy goes off to wizarding school. Ged comes to the wizards' school on the island of Roke untrained and unlettered, but full of talent and eager to prove himself. Showing off his power one night, he unleashes a dark being stronger than his magic can contain, and is pursued by it through the archipelagos of Earthsea, until he decides to turn and be the pursuer himself. It is incredibly rich in details of character, place, and magic, and a cracking good read.
The cover at right is that on the first edition. Ged was written as being from a dark skinned people, and it has been a constant annoyance to Le Guin that this has never come across in any of covers or in the movie version (which has nothing much to do with the story in the book. Here's her take on it: A Whitewashed Earthsea: How the Sci Fi Channel wrecked my books).
Anyway, a Wizard of Earthsea is also a good place to start because it is the first of a series, and there are lots of very nice books that come after it.
My second recommendation would be The Dispossessed (1974), which won both the Hugo and the Nebula Awards in 1975. It explores the life of Shevek, a brilliant mathematician on a planet colonized by idealists who have eschewed all personal property. Shevek's discovery of a way in which communications can pass through space instantaneously puts him at odds with factions of on his own planet, who are afraid of change, and takes him back to the planet from which his ancestors fled. There he must negotiate a society of property and inequality that wants desperately to possess what he has to give. This is an extraordinary book. It is a brilliant portrayal of communal life in a would-be utopian society (the book is subtitled An Ambiguous Utopia), on a planet with a marginal atmosphere, and Shevek is an unforgettable character--the ultimate idealist/intellectual/loner/dreamer/husband/father. I think I have made it sound kind of unexciting, but it is a gripping read and I love it dearly and I think everyone should read it.
And now here is an Ursula Le Guin story of time travel--"Another Story," published in 1994 in an anthology entitled A Fisherman of the Inland Sea.
On the planet of O, Deo grows up listening to his mother tell stories from her childhood on Earth. His favorite is the story of the fisherman, who leaves his family for the sea king's daughter. After one night, maybe more, he leaves her to return to land, only to find that many years have passed, and everyone he loved has died. Growing up, he reliazes that this is her own story- her family on Earth grew old while she traveled away from home, through light years of space.
He himself chooses to follow the same path, leaving his beloved family to study on Hain, a planet not quite so far away. It is, in fact, close enough that when, after a few years, he returns for a visit, only a decade has passed, and those he loves, including his dearest friend Sidi, are still themselves. They are older, Sidi is married, their lives have gone on much further than his.
But back on Hain, Deo and his teachers are coming close to a technology that will allow travel through space without time displacement, and Deo volunteers to try to use it to journey home. He does, and he doesn't make it back. Instead of arriving when he left Hain, he slips back through time to his first journey away from home, and his life, and Sidi's, become another story.
It's a lovely story. It is full of the anthropology that Le Guin does so well (on O, every marriage involves four people); in fact, some might find that there is a bit too much on the customs of that place, and not enough Action. But I myself like the carefully constructed world that is the backdrop for Deo's emotionally intense journey. The resonance of paths that we could have taken, the chance to go back and take them again, makes this one of my favorite of Le Guin's stories.