The New Zealand Herald has an article about the authors of “Holy Blood, Holy Grail” suing the author of “The Da Vinci Code” for stealing their intellectual property.
The funny thing is that there ought to be no way that they can maintain that their book is factual and that someone has stolen it.
If they are describing reality, then that is not their creation and not their intellectual property.
If what they have written is their creation, then it is fictional, which they do not want to admit.