Books
- In Haig’s Shadow: The Letters of Major-General Hugo De Pree and Field-Marshal Sir Douglas Haig, 1914-1918 (Greenhill Books, 2019)
- Wellington (Pocket Giants series, The History Press, 2017)
- Douglas Haig: From the Somme to Victory (Aurum, 2016)
- Command and Morale: The British Army on the Western Front 1914-18 (Praetorian Press, 2014)
- Douglas Haig: War Diaries and Letters 1914-18 (London: Weidenfeld & Nicolson, 2005; paperback edition, 2006). Co-editor with John Bourne
- Command and Control on the Western Front: The British Army’s Experience 1914-18 (Staplehurst: Spellmount, 2004). Co-editor with Dan Todman, and contributor
- The Somme (London: Cassell, 2003; paperback edition, 2004)
- Forgotten Victory: The First World War – Myths and Realities (London: Hodder Headline, 2001; paperback edition, 2002)
- Leadership in the Trenches: Officer-Man Relations, Morale and Discipline in The British Army in the Era of the First World War(Basingstoke: Macmillan, 2000)
- The Challenges of High Command: The British Experience (Basingstoke: Palgrave, 2003). Co-editor with Geoffrey Till and contributor
- Leadership and Command: The Anglo-American Military Experience Since 1861 (London: Brassey’s, 1996; new edition, 2002). Editor and contributor
Articles and chapters
- ‘Endings and Beginnings: A World at War and its Place in Global History’. In Paul R. Bartop (ed.), The Routledge History of the First World War (Routledge, 2022)
- ‘The Second World War in Global History’. In Paul R. Bartop (ed.), The Routledge History of the Second World War (Routledge, 2022)
- ‘All Pretty Well Fed Up and Worn Out’? Morale, Combat Motivation, and the ‘Marshall Effect’ in VIII Corps at Gallipoli’, British Journal for Military History Vol 5, No 1 (2019)
- ‘Strategic Command’. In Jay Winter (ed.) The Cambridge History of the First World War (Cambridge University Press, 2014). Co-author with Stephen Badsey.
- ‘Britain and the Empire at War, 1914-1918: Reflections on a Forgotten Victory’. In John Crawford and Ian McGibbon (eds.) New Zealand’s Great War: New Zealand, the Allies and the First World War (Auckland: Exisle Publishing, 2007)
- ‘Dead cows and Tigers: some aspects of the experience of the British soldier in Normandy, 1944’. In John Buckley (ed.) The Normandy Campaign Sixty Years On (London: Routledge, 2006).
- ‘Not the Same as Friendship: The British Empire and Coalition Warfare in the Era of the First World War’. In Jeffrey Grey and Peter Dennis (eds.) Entangling Alliances: Coalition Warfare in the Twentieth Century: (Canberra: Australian Military History Publications, 2005)
- ‘Restructuring the Infantry’. In Journal of the Royal United Services Institute, February 2005
- ‘The British Army and Air Power’ (co-author with David Jordan). In Peter W. Gray (ed.), British Air Power (London: The Stationary Office, 2003).
- ‘The Australians at Pozières: Command and Control on the Somme, 1916’. In David French & Brian Holden Reid (eds.), The British General Staff: Innovation and Reform (London: Cass, 2002)
- ‘Douglas Haig and Airpower’ (co-author with David Jordan). In Peter W. Gray and Sebastian Cox (eds.), Airpower Leadership Theory and Practice (London: The Stationary Office, 2002).
- ‘Reflections on the Experience of British Generalship’. In John Bourne, Peter Liddle and Ian Whitehead (eds.) The Great World War 1914-45 Vol. I (HarperCollins, 2000)
- ‘The Shadow of the Somme: The Influence of the First World War on British Soldiers’ Perceptions and Behaviour in the Second World War’. In Paul Addison and Angus Calder (ed.), Time to Kill: the Soldier’s Experience of War in the West 1939-1945 (London: Pimlico, 1997)
- ‘The Anglo-American Alliance of 1941-45 Revisited’. The Journal of Mississippi History, Vol. LVII, (1996)
- ‘The Operational Role of British Military Police on the Western Front’. In Paddy Griffith (ed.) British Fighting Methods in the First World War (London: Cass, 1996)