In his new book The Evolution of God , best-selling author Robert Wright examines how the idea of God has changed through history. Bill Moyers sits down with Wright to discuss why he thinks the notion of God — real or not — is imperative to a moral society.

In his new book The Evolution of God , best-selling author Robert Wright examines how the idea of God has changed through history. Bill Moyers sits down with Wright to discuss why he thinks the notion of God - real or not - is imperative to a moral society. "Religion will be the medium by which people express their values for a long time to come, so it's important to understand what brings out the best and the worst in it," says Wright. Wright is editor-in-chief of Bloggingheads.tv , a contributing editor for The New Republic and a contributor to Time and Slate .