Bibliography

World War I

Boghardt, Thomas. Spies of the Kaiser: German Covert Operations in Great Britain during the First World War Era. New York: Palgrave Macmillan, 2004.

Hopkirk, Peter. Like Hidden Fire: The Plot to Bring Down the British Empire. New York: Kodansha International, 1994.

Jensen, Joan M. The Price of Vigilance. Chicago: Rand McNally, 1969.

Koenig, Robert. The Fourth Horseman: One Man’s Secret Campaign to Fight the Great War in America. New York: Public Affairs, 2006.

Mohs, Polly A. Military Intelligence and the Arab Revolt: The First Modern Intelligence War. London: Routledge, 2007.

Morton, James. Spies of the First World War: Under Cover for King and Kaiser. Kew: The National Archives, 2010.

Nicolai, W. The German Secret Service. London: S. Paul, 1924.