2013

O'Brien, P. (2013) The American press, public, and the reaction to the outbreak of the First World War. Diplomatic History . ISSN 0145-2096 (doi:10.1093/dh/dht020) (In Press)

O'Brien, P.P. (2013) The Bermondsey By Election of 1909. In: Otte, T. and Readman, P. (eds.) A History of British By Elections. Boydell Press. ISBN 9781843837800

O'Brien, P.P. (2013) How the Second World War was Won: The Anglo-American Air and Sea Destruction of Germany and Japan. Cambridge University Press. (Unpublished)

2011

O'Brien, P. (2011) Herbert Hoover, Anglo-American relations and Republican Party politics in the 1920s. Diplomacy and Statecraft, 22 (2). pp. 200-218. ISSN 1557-301X (doi:10.1080/09592296.2011.576523)

2010

O'Brien, P. (2010) The 1910 elections and the primacy of foreign policy. In: Mulligan, W. and Simms, B. (eds.) The Primacy of Foreign Policy in British History, 1660-2000. Palgrave. ISBN 9780230574724

O'Brien, P. (2010) American strategy in the Pacific after midway: from parity to supremacy. In: International Forum on War History, 30 Sep 2009, Tokyo, Japan.

2007

O'Brien, P.P. (2007) Warfare and the rise and fall of national power. War in History, 14 (2). pp. 265-278. ISSN 1477-0385

2004

O'Brien, P.P., (Ed.) (2004) The Anglo-Japanese Alliance, 1902-1922. Series: RoutledgeCurzon studies in the modern history of Asia. RoutledgeCurzon, London. ISBN 0415326117

2001

O'Brien, P.P. (2001) The Titan refreshed: imperial overstretch and the British Navy before the First World War. Past and Present, 172 . pp. 146-169. ISSN 1477-464X (doi:10.1093/past/172.1.146)