This is Metropolis, the novel that the film's screenwriter -- Thea von Harbou, who was director Fritz Lang's wife, and a collaborator in the creation of the film -- this is the novel that Harbou wrote from her own notes. It contains bits of the story that got lost on the cutting-room floor; in a very real way it is the only way to understand the film.
If you're a fan of Lang's silent masterpiece, then by all means check this novelization out. However, as only as a curiosity. Yes it does expand the film's story quite a bit, but Von Harbou's writing style ruins this cinematic masterpiece with overexcessive repetition of phrases almost every chapter. Such a shame that the novel lacks Lang's directorial genius, but it's still an interesting read for fans of the movie. Otherwise, it's a story tbat is better off seen than read.