Eunan O'Halpin MRIA is the Professor of Contemporary Irish History at Trinity College, Dublin. He is also an editor of the Documents on Irish Foreign Policy series. His most recent publications are: Head of the Civil Service: A Study of Sir Warren Fisher, Defending Ireland: The Irish State and its Enemies since 1922 and MI5 and Ireland, 1939 ? 1935. He is a co-editor of Documents on Irish Foreign Policy: Volume I, 1919-22, Documents on Irish Foreign Policy: Volume II, 1923 ? 1926 and Documents on Irish Foreign Policy: Volume III, 1926 ? 1932. He is currently co-editing a study of Anglo-American security co-operation between 1914 and 1949.