The books were so convoluted and had so many sub plots going that by the fifth book the author could only address half his characters in each new book. It finally got to the point that the TV show couldn't wait for his next book to base their episodes on so they started making up their own plots (with the authors permission and input). I think the last three or four years of the TV show didn't have a book story line to follow although the author claimed the show ended the way he had planned on ending the book. Of course the TV show had to skip over 75% of the sub plots and change some of the main story line but it still got the main characters and plot right.