Peter Duffy is an author and journalist based in New York City. He has written three books of historical non-fiction – The Bielski Brothers (HarperCollins, 2003); The Killing of Major Denis Mahon: A Mystery of Old Ireland (HarperCollins, 2007); and Double Agent (Scribner, 2014). His journalism has appeared in The New York Times, New York magazine, The Wall Street Journal, Slate, the New Republic, and many other publications.