Gone Girl influenced Gone Girl

Fincher's film, screenplay by Gillian Flynn adapting her own novel, which is why it keeps the structural trick most adaptations would flatten: the alternating his-and-hers narration, and the mid-book reveal that Amy's diary is a fabrication written to be found. The film reproduces that with voiceover and a hard tonal break at the reveal. The ending is the novel's, not a softened one, which was widely expected to change and did not.