The Night World connection in this book is tenuous, but it does make sense. After all, in a world populated with werewolves, vampires, and other supernatural creatures, it's natural that spirits would exist as well. So far Gillian is probably the most identifiable of all the protagonists in the Night World books, as she's your everyday teenage girl who finds out that there's a secret world...and she's part of it. How many of us have wished for that? I know I have.
The first nine books from the 'Night World series were originally published in 1996–1998 by . The release of the tenth and last book, , was put on hold when L. J. Smith took a hiatus from writing sometime in 1999. In 2008, the nine Night World books were reprinted in three omnibus volumes.