Charles Darwin’s “On the Origin of Species” is arguably the most important book of the 19th Century. University of Tulsa professor Randall Fuller joins us to talk about how the book’s argument for a common ancestry for all creatures was used as a potent argument against slavery. He writes about the idea in “The Book That Changed America: How Darwin’s Theory of Evolution Ignited a Nation” (Viking). Study up for the conversation by reading Chris Vognar’s Dallas Morning News review of the book.