Daniel J. Sharfstein is a professor of law and history at Vanderbilt University and a 2013 Guggenheim Fellow. His first book, The Invisible Line: A Secret History of Race in America, won the J. Anthony Lukas Book Prize for narrative nonfiction. His new book, Thunder in the Mountains: Chief Joseph, Oliver Otis Howard, and the Nez Perce War, is coming out in April. He lives with his family in Nashville, Tennessee.