This week Ron and Ed welcome Chelsea Follett to talk about her book, Centers of Progress: 40 Cities That Changed the World. From the book: Where does progress happen? The story of civilization is the story of the city. It is cities that have created and defined the modern world by acting as the sites of pivotal advances in culture, politics, science, technology, and more. There is no question that certain places, at certain times in history, have contributed disproportionately toward making the world a better place. This book tells the story of 40 of those places. In Centers of Progress: 40 Cities That Changed the World, Chelsea Follett examines a diverse group of cities, ranging from ancient Athens to Song-era Hangzhou.