Peter S. Onuf, a senior research fellow at the Robert H. Smith International Center for Jefferson Studies at Monticello and Thomas Jefferson Foundation Professor of History Emeritus at the University of Virginia, has written extensively on sectionalism, federalism, and political economy, with a particular emphasis on the political thought of Thomas Jefferson. Onuf is a cohost, with Ed Ayers and Brian Balogh, of the radio show BackStory with the American History Guys. The show can be streamed through its website, downloaded via podcast, or listened to live on 38 local radio stations. Most recently, Onuf has published a collection of essays, The Mind of Thomas Jefferson (2007) and a work co-authored with his brother, political theorist Nicholas G. Onuf, that focuses on the history of international law and order in the Atlantic states’ system during the Age of Revolutions and early nineteenth century. The book is entitled Nations, Markets, and War: Modern History and the American Civil War (2006). His current research focuses on Jefferson and the origins of American democracy.