The character is an insomniac with a split personality, and is depicted as an unnamed everyman (credited in the film as "the Narrator") during the day, who becomes the chaotic and charismatic Tyler Durden at night during periods of insomnia.

When an impostor named Marla Singer begins to appear at the groups, his euphoria is broken and his insomnia returns.

The Narrator meets a man named Tyler Durden in an airplane, and begins living with him after his condominium explodes due to unknown causes.

Tyler initiates a cult-like organisation known as Project Mayhem in order to aggressively promote his anti-consumerist ideals, but the Narrator becomes increasingly uneasy with the group as its activities become more destructive.

Later, he regains consciousness in a mental hospital, believing he is in Heaven, and imagines an argument with God over human nature.

These quotes refer to the Narrator's reading old Reader's Digest articles in which human organs write about themselves in first-person perspective.

[6] Set ten years after the original novel, the Narrator is depicted as working for a private military contractor, while he and Marla are married and have a nine-year-old son named Junior.

[9] Unlike in the film, Tyler's appearance is based on a personal friend of the author, depicted as having "shoulder-length-Jesus blond hair.

In the 1999 film Fight Club, based on the Palahniuk novel and directed by David Fincher, the Narrator is portrayed by Edward Norton while Tyler is played by Brad Pitt.