Research Conrad's concept of the dark side of man and how he uses this theme in various works. How is the concept of a dark side of human nature treated in other disciplines, for example, in psychology or philosophy?

Discuss how Leggatt and the captain are related. Is Leggatt a double for the captain? What does the captain learn from Leggatt? Does Leggatt learn anything from the captain?

Compare the relationship between Leggatt and the captain in "The Secret Sharer" to the relationship between Kurtz and Marlow in Conrad's novella, Heart of Darkness.