I enjoyed this Thunder Peak with it's western flare (Arizona setting) mixed with a fantasy world with unicorns, fighting turtles and lizards, and a character - Nightingale - who is dark and unpredictable. The story is well written and highly entertaining, and the characters came to life. Full of action and intrigue, the young girl, Casey, is a brave and caring teenager and her relationship with Jonas is loving and representative of what a good parent/child relationship is all about. I was pleased to read this book because it wasn't a 'dark' fantasy at all but full of adventure, which is why I think it's appropriate for middle grade and up. I think this book appeals to readers who like books like The Chronicles of Narnia in the sense that it is not overly graphic or dark. An overall good adventure mixing the feel of a Western with the adventure and fantasy of supernatural creatures.