Before the invention of television and film the art of story telling was restricted to theater and literature. Theater was and still is performed live by actors who tell some kind of story through their performance. But theater is still limited greatly in its ability to convey setting to the viewer. In order to fully grasp the power of any story one must believe, in a sense, that the events are happening before them. Literature is better able to accomplish this by utilizing the power of the human imagination. Even more than this literature has the ability to describe human emotion through the use of strong metaphors and colorful language. It is this technique of writing that remains unique to literature. Even film cannot approach the human emotion and heart that literature has given people over the ages. Yet film is not without advantages of its own. Film can have strong power behind it. A kind of power that a viewer is forced to see and feel. This power is delivered though a film's soundtrack, it's quick pace, and in recent years, the use of special effects. Good books are often made into films. Which is better? The answer to that question depends on the intentions of the author of the book.
Both film and literature are a form of art. They are fiction and they create a false reality and a plot that is bound by that false reality. When comparing the two the intentions of the artist must be considered. When John Steinbeck wrote The Grapes of Wrath he intended the book to be sort of modern day epic that modeled the patterns of old world epics such as The Odyssey. Steinbeck wanted people to read a book that would take them into the human side of the troubles facing many farmers during the Great Depression. The book includes interchapters that do not advance the plot but serve only to offer another, more general point of the events being presented in the actual story. An attempt to model something like this in film would be futile as its meaning would become lost.