What is the theme in Cloud Atlas by David Mitchell?

Time and duplicity are themes in this story. All of the six stories in Cloud Atlas contain at least one person who is acting in a duplicitous manner out of greed. In "Adam Ewing," it is Dr. Henry Goose, who is trying to poison Ewing in hopes of robbing him. In "Letters from Zedelghem," it is Frobisher, who pretends to be a musical helpmate, but is actually acting on his own agenda, while stealing books and seducing the women of the house.