His book The Pope and Mussolini: The Secret History of Pius XI and the Rise of Fascism in Europe (2014) won the 2015 Pulitzer Prize for Biography or Autobiography.
Buku buatannya The Pope and Mussolini: The Secret History of Pius XI and the Rise of Fascism in Europe (2014) memenangkan Penghargaan Pulitzer untuk Biografi atau Autobiografi tahun 2015.