It can be notoriously tough to predict what will capture the imagination of the general public - history is littered with crashing failures such as Sir Clive Sinclair's battery electric vehicle, the C5, and unbelievable successes such as Facebook, which started out as a university-based social network and is now the world's largest database of cat and lunch photos. If life was easy to predict, there'd be infinitely more lottery winners. Hollywood executives are no different in this respect. Every commission of a film such as Heaven's Gate or Waterworld proves this. For every sleeper hit and expensive disaster, there are films that should never have worked and hit the screen against all odds- and were undeniably terrific. Here, we take a look at 5 such films that were adapted from source material that should have ensured that the transition from page to multiplex could never have happened, whether it be from the complex narratives, the controversy of the novel's plot or the sheer lack of technology available to bring the book to life.