The Loss of the Diamond (1848), the events related by Gabriel Betteredge, House-Steward in the service of Julia, Lady Verinder
Gabriel Betteredge is reading Robinson Crusoe by Daniel Defoe, his favorite book in the world, when Franklin Blake comes in to ask him a favor.
He wants Betteredge to write down everything he remembers about how the Moonstone was lost.
Betteredge must only include the events that he witnessed personally – other people will take up the story and tell it from their points of view, as well, after the events that Betteredge knows about have been described.
Betteredge agrees to try.
He's over seventy years old, and has been a servant in Lady Verinder's house since he was a boy, so he feels a lot of loyalty to the family.
He also likes to use Robinson Crusoe as a way of telling the future – whenever he's in doubt about something, he opens the book at random, and reads the page looking for advice.