If it's a good work of adaptation, the book should remain a book and the film should remain a film, and you should not necessarily read the book to see the film. If you do need that, then that means that it's a failure. That is what I think.
Marjane SatrapiThe novels have done so well because the drawings are abstract, black-and-white. This adds to the universality of the story. "Persepolis" also has dreamlike moments, and the drawings help maintain cohesion and consistency.
Marjane Satrapi