The action and violence and battle scenes in this series tend to mark it for a male audience, but the characters and plots are well enough developed that I and some other female friends have enjoyed it also.  Given the violence, these books may be most fitting for middle school and high school audiences, but a good friend who is also an elementary librarian says she’s got a lot of fifth grade boys who love the series,   so I’ve added the complete collection to my shelves as well, but I only market it to fifth graders.  This, the eighth book in the series, takes place when Will has ceased to be an apprentice, and is a Ranger in his own right, but he’s teamed up with his former mentor and warrior friend to form an emergency squad sent to squash the growth of a cult who is taking over a neighboring country, stealing people blind and gradually over-taking the established authorities.