Megan Whalen Turner is the author of the excellent (possibly ongoing?) children’s fantasy series featuring The Thief, The Queen of Attolia, and The King of Attolia. Borrowing freely from Greek mythology, Whalen’s books are intelligent, thoughtful novels featuring some very complicated interpersonal relationships.
Aftertaste: That “complicated interpersonal relationships” bit mentioned above means that these novels probably aren’t suitable for kids under age 13. While there is absolutely no explicit sex or violence in these books, the main romantic storyline goes down some extremely unusual paths. It’s meant to raise some eyebrows, and it would be a shame if the reader were too young to appreciate the complexity of the relationship Whalen has created.