One of the most common and clichéd questions in reading groups is, Which was better: the book or the movie? In order to retain your elitist card you must unhesitatingly announce, The Book, of course! But it’s not always true.
Many times the authors, even though their books are quite good, tend to spread the narrative loosely over several characters and numerous scenes; they might even throw in a secondary plot or two or a particularly juicy love interest. Then when they go to make the movie they discover that all the by-the-page profits from the original publisher are never going to cover the extra cost for film and self-absorbed actors, so the writer of the movie script might combine a few characters or scenes, eliminate extraneous material which is not needed to advance the narrative, and hopefully create a tighter, more marketable product for the Silver Screen.