April 1, 2010 -- What does it mean to be "white"? Is it one race of people? Were people defined as "white" hundreds of years ago? In her new book, "The History of White People," author Nell Irvin Painter tells the story of what she considers a forgotten chapter in history: the story of whiteness. From antiquity to the modern era, Painter explores the concept and how the definition of "white" has taken on many forms.
In today's Conversation, Diane Sawyer asks Painter how notions of "whiteness" came to be. They discuss how white beauty has affected definitions of beauty in general, the origin of "Caucasian" and whether such a term can accurately describe someone. And Painter ponders the question of whether we live in a truly post-racial society.