It was the TV show that wrote it. The creaters/writers of Castle and Nathan Fillon wrote it, to give the show a new curve. A real writer, off of a TV show..... with a book in that TV show.... and that book is in stores. Think about it. Would you get hooked on a TV show if your favourite author is on it? I certainly would. I hope I answered your answer, good enough! :)
I think it's fantastic how they make the books look like Castle really wrote them when you know he didn't. Even the Bio on the back cover. Very ingenius. rockynj