It used to be that you read the book and then, a couple of years later, you saw the movie. But recently, it's been happening the other way around.
Especially interesting is the fact that sometimes the book starts as a figment of the filmmaker's imagination.
For instance, according to The Christian Post, in the upcoming Christian movie "Fireproof" (scheduled for release on Sept. 26), screenwriters created a book as plot point. The movie tells the story of Caleb Holt, a firefighter with a troubled marriage. To help prevent divorce, Caleb's dad suggests he read a book called "The Love Dare."
The book changes Caleb's view of marriage and transforms his life. As soon as preview audiences saw the film, they began flooding bookstores with inquiries.
The only problem: The book didn't exist.
It does now, however.
Brothers and associate pastors Alex and Stephen Kendrick, also co-directors and producers of "Fireproof," sat down and penned such a book in the space of a few weeks. It hasn't hit bookstores yet but has already sold 300,000 copies and may go on to become the bestselling Christian book of 2008.
On the opposite end of the spectrum, there's the story of the "Sex and the City" book. When Carrie Bradshaw (Sarah Jessica Parker) sat in bed reading a book called "Love Letters from Great Men" in a scene in the film, women viewers everywhere decided they needed a copy.