Buy it Now!
You have got to love the tag-line for the book "Night Mare!" "The danger to Xanth was so great that only a night mare could offer hope!" Night Mare's in a Xanth are a little different than what we are used to here in our Mundane existence. In Xanth, things tend to be more literal, and Night Mare's are actual Mare's who's job it is to deliver the bad dreams to the citizens of Xanth.
One Night Mare, Mare Imbrium, has been given a special mission. Normally the Night Mare's can't go out during the day, but because she has half a soul (see the book "Ogre, Ogre) the Night Stallion is able to give her special dispensation. Now she has a special message for the King of Xanth, and she is destined to become a liaison between him and the Night Stallion.
The people and government of Xanth undergo a lot of changes in this book, but they are for the better! I really enjoyed reading it and I look forward to seeing where Piers Anthony takes us next.