The typical relationship between a book and its adapted film is that the book gives more insight into its characters internal lives and goes much deeper in exploring its ideas. As a film, Children of Men is already packed with interesting concepts and I had hoped for more of them in the source material. As it turns out, the film may be superior to the book in most ways.
============= Everything Spoiled =================
Lots of detail on both the book and film ahead. Tread carefully if you haven't at least seen the film. It's probably my favorite from the last 10 years and you'd be denying yourself a great story by not going into it unawares. As for the book, I wouldn't worry about spoiling it.
- The book's world is one of idyllic decay, not hellish dystopia. The protagonist is a tweedy Oxford history professor. Crime is low, real estate is cheap.
- The book's treatment of immigrants is significantly more benign. The film calls them "fugees" and details the government's witch hunts to remove them from fortress England. In the book, they are "Sojurners", younger guest workers with few rights imported to provide necessary labor.
- The film splits Julian's role into two characters: resistance leader and immigrant Kee. With the film's more hyperbolic treatment of the fugees, this makes the Fishes' and mother's reluctance to work with the government more narratively sensible. It also creates greater dramatic irony.
- The film compresses the characters of Helena (Theo's ex-wife) and Julian (a resistance leader) into the same character. This makes Theo's involvement seem better-motivated.
- The climax of the film takes place at an unpoliced internment camp, probably modeled after the book's Isle of Man prison colony. We never see the colony in the book, to its detriment.
- Theo's cousin Xan is the "Warden" (dictator) of England in the book, while he heads an arts project called the "Ark" in the film. This colors the Resistance's expectations of Theo and creates a more useful role for him to play. It also creates a memorable scene with a crudely-repaired David statue and iconic Guernica behind the dinner table.
- The novel's Fishes are just 5 incompetent idealists with a bullet list of grievances against the Warden of England. In the movie, they are a global resistance organization. The film's version raises the tension, but retains Theo's dismissive attitude about them.
- Jasper and his wife are more compelling characters in the film. She is given a more telling backstory which integrates more into the world and the government's repressive nature.
- There are a few interesting ideas from the book which do not appear in the film. People increasingly treat pets as children, forcing kittens into baby clothes. The Church of England is internally divided over whether its priests can officiate christenings for puppies. I enjoyed these details in the slower-paced book, but probably would have found them distracting in a movie.
The film creates a more plausible, compelling, and kinetic set of events and actually contributes more original ideas. This joins my short list of stories which work better in adaptation than the original. Also present: Clockwork Orange (more visceral), Hunt For Red October (less jingoism, more suspense), Lord of the Rings (less elvish poetry).