Peter Duffy is a writer based in New York City. He is the author of four books — The Bielski Brothers (HarperCollins, 2003), The Killing of Major Denis Mahon (HarperCollins, 2007), Double Agent (Scribner, 2014), and The Agitator (Public Affairs, 2019). His journalism has been published in The New York Times, New York magazine, The Wall Street Journal, Slate, and many other publications.