The Princess of Cleves
A tale of courtly intrigue, romance, and political games, into which the titular Princess finds herself swept up.
I went into this book not expecting to like it, but it's absolutely phenomenal. Tightly plotted, with a rich sense of irony, and a peek into the unforgiving court life. Without spoiling too much, it's also a complete heartbreaker. Usually I don't enjoy courtly books, but this one has completely converted me.