The Horse and His Boy by C.S. Lewis

This is the third book in the Narnian Chronicles by C.S. Lewis. It is the story of a boy, Shasta, who is forced to choose between slavery or setting out for the unknown land, Narnia with a talking horse, Bree. Shasta of course chooses the latter and ends up having many adventures and making new friends along the way. Shasta eventually realizes that he is actually from Narnia all along and was stolen as an infant to prevent his fufilling a prophecy that he would save Narnia from grave danger in the future.
I read the Narnian Chronicles as a child and rereading this story was nostalgic and fun. There is a lot of subtle humor that I do not think I understood when I read it the first time. My main qualm with the book is that the Christian message can get really in-your-face and unless you are religious some of the parts involving Aslan can be a little cheesy.
For example:
"Who are you?" Asked Shasta.
"Myself" said the Voice, very deep and low so that the earth shook: and again "Myself," loud and clear and gay: and then the third time "Myself," whispered so softly you could hardly hear it, and yet it seemed to come from all round you as if the leaves rustled with it (page 176).
Parts like this occur a little too frequently and may seem overdone to a non-religious reader like me.
Overall this is a fun adventure story and the recurring characters and references to other events in previous books would probably draw readers in and keep them interested. I would keep this book in the classroom but not make it required reading.