What is the theme in A Planet Called Treason by Orson Scott Card?

Travel creates understanding and tolerance is a theme. Until Lanik leaves his home, he is certain that the whole world is just like his own land, which in his case is full of violence, class prejudice, and war. Until people grow up and leave home, or read books, as Lanik later does during his travels, there is no way for anyone to know that there are different kinds of living elsewhere. Lanik learns quickly as he goes on his hero's journey. In the land of Nkumai, he learns that people don't always say what they mean. They can talk high ideologies and ideals but underneath, they can be living in a very different way.