The Horse and his Boy

The horse and his boy was the most unusual of the 7 Narnia books. The main characters weren't people from our world. It was set entirely in Narnia . .well . .not Narnia but set entirely in the Narnia Universe. Someone once said to me that they didn't like it for this reason, but I loved it. Seems meant for slightly older children than the other Narnia books, can't remember really as years since read it. Have read them as an adult though. One of the customer reviews on USA Amazon says:

I scanned through the one-star reviews and found that very few adequately conveyed the naked racism and sexism that taints this book. If this book were written today, it would rightfully fail to even find a publisher without serious revisions. Our society has progressed beyond Lewis's worst prejudices which he gives free rein (ha! Pun!) in this silly and--quite frankly--offensive story.

At least it doesn't suffer from speciesism as it would have done if called the boy and his horse.