Nunzio Pernicone was professor emeritus in the Department of History and Politics at Drexel University. He is the author of Italian Anarchism, 1864-1892 and Carlo Tresca: Portrait of a Rebel. He died in 2013. Fraser Ottanelli is a professor of history at the University of South Florida. His books include The Communist Party of the United States from the Depression to World War II and he is also coeditor of Letters from the Spanish Civil War: A U.S. Volunteer Writes Home.