Tryntje Helfferich received her M.A. from the University of New Mexico, Albuquerque, and her Ph.D. in early modern European history from the University of California, Santa Barbara. She studies German central Europe during the early modern period (1450-1815), with a particular focus on the Reformation and the Thirty Years War (1618-1648). She is interested in the history of ideas, the history of war and society, the history of religion, and diplomatic history. Her publications include The Essential Luther (Hackett, 2018); The Essential Thirty Years War (Hackett, 2015); The Iron Princess: Amalia Elisabeth and the Thirty Years War (Harvard, 2013); On the Freedom of a Christian (Hackett, 2013); and The Thirty Years War: A Documentary History (Hackett, 2009).