Almost a universal truth, as the movie almost always seeks to summarize and shorten the book into two hours or less. Thus, the book is much more detailed, and in the case where the movie is very much unlike the book, it's probably a lot better. The book is also much more absorbing because it requires the reader to actually digest the words and paint a picture of what's occuring in their mind. Rather than being a passive audience that uses merely the visual and auditory senses, the reader has to use their imagination; a very alien concept these days.