Blue Moon is the 8th book in the Anita Blake: Vampire Hunter series by Laurell K. Hamilton
Blue Moon takes Anita to Myerton, Tennessee to help clear Richard of rape allegations. In the process, Anita and her allies are drawn into a supernatural conflict with the Master Vampire of that city, Colin, as well as the criminal scheme that Richard's frame-up was meant to conceal.
During Richard's investigation, Anita juggles being a leader among both the werewolves and the wereleopards, a job that is getting harder and harder. Anita and Richard reconcile during the book, with Richard offering to accept Anita's continued involvement with Jean Claude as long as Anita accepts that Richard isn't monogamous either.
This is the first book where we see Marianne, Anita's magical Wiccan mentor. Marianne is not a lycanthrope but works with the local werewolf pack in Tennessee and she begins teaching Anita how to be a better leader of the wereleopards.
We learn Damian is showing signs of being Anita's vampire servant and that Jean Claude gains power from sex. The latter frightens Anita enough that she demands a break from both Jean Claude and Richard; Marianne helps her to temporarily close off her metaphysical "marks" to them.
As with previous novels, "Blue Moon" refers to a location within the novel itself. In this case, the "Blue Moon cabins" are a set of rental cabins owned by Verne, the local Ulfric of the werewolves. "Blue moon" is also used to refer to an upcoming full moon, the second in that calendar month, which is a rare occurrence.