“Based on the book” is a phrase sometimes applied loosely to films. “Inspired by” is a somewhat more accurate albeit much more imprecise expression of the basis for source material. Still more liberally invoked in cinema is “based on a true story.” In Peter Weir’s The Way Back we have a film that is very loosely based on the book The Long Walk, purportedly presenting a true story, the veracity of which has been called into doubt on several occasions.
None of that should really matter because when we watch a film we should be judging it on its own merits and not on whether it’s similar to the book or not, or if it’s a true story. But the problem is that presenting your film up front as being based in fact tends to color the audience’s judgment of the events depicted.
