One day she told him there was a man raking leaves in the garden. Martin could hear nothing, and decided his mother was lying. He used a camera to take a photograph of the garden. It is his way of checking up on his friends. He takes pictures, has them developed, asks people to describe them to him, labels them in Braille, and is alert to any contradictions in what people tell him.
Martin lives alone, in a rigid and compromising lifestyle, and is fiercely independent.
If he feels he is being overlooked in a restaurant, for example, he is capable of taking a bottle of wine and pouring it out on the table until a waiter takes notice. Celia is Martin's housekeeper. Actually, she doesn't need the work to support herself. It is her way of getting into Martin's life. She is a photographer herself.