Legend of Bass Reeves
What I love about this book is that is combines Nonfiction with Fiction. The book is separated into sections (there is a clear bias from Paulsen about "true history vs. legends). A nonfiction section will be paired up with what Paulsen has guessed happened. This makes for some great reading that is also educational and interesting.
I would highly recomend this book to teachers teaching a unit on slavery or the Old West.