I don't know if this counts as underrated or not, but I'm choosing it. Underrated can mean underappreciated and this book certainly falls under that category. Definitely The Blue Castle! Because while I've seen this one around the blogosphere several places, I'd never heard of it until I started reading reviews. Anne (of Green Gables fame) is so widely known and poor Valancy just gets the short end of the stick. (Even in her own story!) As wonderfully good as this book is, I really can't figure out why more people don't seem to know about it. When I mention to friends how much I loved it, they have no idea what book I'm talking about. (Well....to be honest this is typical as most of my real life friends don't read. But still! My point stands. *nods* Yes indeed.) Watching Valancy find her brave is so inspiring and I can attest that several rereads do not diminish her awesomeness!
Long story short? More people need to read this book! The end.