What were the reasons behind Camus receiving the Nobel Prize for The Stranger?

Through The Stranger, Camus explores his own pet philosophy: the absurd. In short, absurdism says the world is devoid of rational meaning. But you can read more about that in our discussion of "Themes: Philosophical Viewpoints." The Nobel Prize Committee quite rationally thought Camus should win some money, so they gave him the Nobel Prize for Literature in 1957, not for The Stranger per se, but for his generally "important literary production, which with clear-sighted earnestness illuminates the problems of the human conscience in our times."

Ps. If you like Camus you should check out his short story "The Guest". It's one of my favourites!