Which brother wrote the short story that inspired Nolan's Memento?

Jonathan Nolan wrote the short story that inspired Christopher Nolan's Memento. The story, titled “Memento Mori,” shares the film's core idea of a man unable to form new long-term memories while pursuing the person responsible for his wife's death.

The brothers developed the project during a 1996 cross-country road trip from Chicago to Los Angeles. Jonathan discussed the premise with Christopher, who began developing a screenplay, while Jonathan continued writing the short story. Their versions evolved at the same time through correspondence and exchanged drafts.

“Memento Mori” differs substantially from the finished film. Its protagonist is named Earl rather than Leonard Shelby and is a patient in a mental institution. Like Leonard, Earl relies on notes and tattoos because he cannot retain new memories, but the story follows its own path and ending.

The short story was published in 2001, after Memento had already been released. That timing helped explain why the film was initially treated as an original screenplay during awards season. The brothers ultimately received the film's major writing credit together, while Christopher directed the 2000 movie starring Guy Pearce.