By Shannon Hale.
A great fairy tale somewhat in the lines of Robin McKinley's retellings. This one is based on the Brothers Grimm tale "The Goose Girl", and was quite enjoyable to read, although there were parts where Ani/Isi's naivety was painful enough to make me put the book down before continuing onward. Definitely recommended if you like any sort of fantasy or fairy tales or stories that end well. There is one somewhat mature reference, but I find that in this case "mature" isn't necessarily a synonym for "dirty."
I didn't like it's successor (or "companion novel") Enna Burning quite as much, but it was also a decent read. I'm still waiting on River Secrets, the third volume in the series.
If you like fairy tales (and don't take yourself too seriously) you might also enjoy No Rest for the Wicked, a clever webcomic that starts with the Buried Moon and makes good its escape.