What is the theme in Cloud Atlas by David Mitchell?

Things being not what they seem is another theme in this book. In each of the Cloud Atlas chapters, there is at least one person who is not what he at first appears to be. In the "Adam Ewing" chapters, it is Dr. Henry Goose, who initially seems to be an amicable middle-class English doctor, but who turns out to be a murderous adventurer. He befriends Adam Ewing and exploits his hypochondria with the purpose of poisoning him with arsenic and stealing his money and belongings.