Must a film adaptation be faithful to the book?

Axis: faithful to the book ... free to change

John

date	change	position	video
2007-05-16	new	John thinks the screenplay is pretty good even though it is way different from the book.	Brotherhood 2.0: May 16: Beating the EBO into the ground 00:00:40
2008-10-29	restate	John says a movie can't ruin a book and that a proper adaptation must radically change nearly everything about the book.	The Unzipped Zipper (Of Your Pants) 00:01:23
2013-09-17	restate	John, as the author, says details like the actor's hair colour not matching the book don't matter to him at all.	Question Tuesday with Nat Wolff (aka Isaac in The Fault in Our Stars movie) 00:01:14
2013-10-22	restate	John says a film cannot and should not be the same as the book, since it tells a visual rather than textual story, though he found the script very faithful.	Question Tuesday: The Fault in Our Stars Movie Edition 00:01:27