Normally, adaption of a popular or appreciated novel seems like a good idea because obviously something about the story, or characters, or tone etc., was strong enough to attract readers in the first place. That attraction could translate to a connection with film audiences. The movie could just visually shows us a version of what we were picturing in our heads anyway. However, many readers who watch the film versions of their beloved books are invariably disappointed. Plot has to be cut down due to time restraints, we aren't usually exposed to characters' inner monologues or even get to know them as well, and even sometimes, producers/directors decide to change plotlines or endings to make the story more "accessible." I would have to agree that the majority of the time, the film will never be as good as the book...but maybe things are changing?
No Country For Old Men is based on a fairly mediocre book by Cormac McCarthy. (You can read my GoodReads review here) In this case, the film keeps the tone and themes from the book, and actually for the most part, stays fairly true to the story. However, the book just doesn't make for a very satisfying read, but does adapt nicely to the Coen Brothers' vision. The main departure happens by eliminating a character and a small side story involving a teenage girl that Moss picks up while she's hitchhiking, but very explicitly never evolves into anything sexual. The purpose of her existence in the novel is unclear, other than to place doubt in the mind of Moss' wife regarding his fidelity. Her almost complete absence in the film is welcome and I believe only make the film stronger and easier to follow.
While I wouldn't say the McCarthy novel was bad per se, I cannot refrain from assigning that description to Oil!, the Upton Sinclair novel that There Will Be Blood is loosely based on. (Once again, GoodReads review here) In this case, PT Anderson keeps very little from the original story. The characters that even make it on the screen have different names, temperaments, and agendas. Daniel Plainview is an infinitely more interesting and complex character than his inspiration, J. Arnold Ross. Ross is basically good at finding oil, loves his son, and pays off government and city officials when he needs to get something done. He is far from obsessed or borderline evil or even descending into his own downward spiral, and consequently one doesn't find much to react to in the book. Also, the book is told through the eyes of Ross' son J. Arnold Ross Jr., aka "Bunny." Bunny is already a teenager at the outset of the story, compared to the young boy "H.W." in the film. There is no tragedy to befall the young oil protege, other than his own conscience...yawn. Eli Sunday used to be Eli Watkins. He still leads a questionable church, but almost no interaction with the big oil man, and certainly no form of confrontation...Where the film succeeds in questioning both capitalism and religion, the book utterly fails. It doesn't really try to tackle much in the way of religious corruption, but goes completely overboard on attacking capitalism, transforming the novel into a 550 page debate between capitalism, socialism, and communism. At its core, I even agree with what Sinclair is getting at, but I couldn't have been more bored with his literary methods. On the other hand, I had no problem sitting through PT Anderson's 2 and 1/2 hour loose interpretation of a similar theme.
Maybe what these successful films of last season show us, is that in order to make a good film adaptation of a novel, perhaps the original material should be a little sub-par...giving the film the opportunity to rescue whatever may have been of value...