I beg to differ, and cite the example of Jurassic Park (the first one). Very little in the film was explained (@ least compared to the novel), certain characters were changed, and the ending of the film was drastically altered (in the end of the book, Isla Nublar is nuked). Does this make the film any less of a good film? NO! I could go on and on about the alterations that were made to the LOTR trilogy that no amount of expansion could possibly correct, and while I agree with many of the changes made, I disagree with almost as many. Are they still good films? YES! They may not be the perfect adaptations of the novels, but they work well cinematically, and the truth is, no adaptation will ever be truly perfect, because everyone who reads a novel perceives it in a different way; the fact that Cuaron's version of Prisoner of Azkaban has incited such discussion is a good sign. Why? Because it means that not everyone is willing to take Hollywood's word as gospel. I think it's a good adaptation because it takes chances on the audience's familiarity with the novel, and it has polarised fans of the films and the novels. Only a really good piece of filmmaking can do that. If everyone is in agreement as to quality, something is wrong.