Redwall by Brian Jaques*

Cluny, the one eyed rat, threatens the peace at the abbey of Redwall.  The mice long for the legendary sword of Martin the Warrior to help them to win this seemingly impossible battle.  Enter, Matthias, an unlikely hero . . .

My eleven year read this book to himself to support our study of Medieval.  He liked this book a lot  . . .maybe even better than The Ranger's Apprentice and The Brotherband (he has to read more in the series to come to a definite conclusion).
Warning: one d--n word
*Highly recommend.
-Borrowed from the library.
The library categorizes this series as "young adult".