The Sleepwalkers by Christopher Clark

Acknowledgements
    On 12 May 1916, James Joseph O’Brien, grazier, of Tallwood Station in northern New South Wales applied to enlist in the Australian Imperial Force. After training for two months at the Sydney showgrounds, Private O’Brien was assigned to the 35th Battalion of the 3rd Division of the AIF and embarked on the SS Benalla for England, where he received further training. On around 18 August 1917, he joined his unit in France, in time to take part in the battles of the Third Ypres campaign.
    Jim was my great-uncle. He had been dead for twenty years when my aunt Joan Pratt, née Munro, gave me his wartime journal, a small brown notebook full of packing lists, addresses, instructions and the odd laconic diary entry. Commenting on the battle for Broodseinde Ridge on 4 October 1917, Jim wrote: ‘It was a great battle and I have no desire to see another.’ This is his account, dated 12 October 1917, of the battle of Passchendaele II:
    We left the details camp (which was close to Ypres) and made for the Passchendaele sector of the line. It took us ten hours to get there and we were tired out after the march. Twenty-five minutes after arriving there (which was 5.25 on the morning of the 12th) we hopped over the bags. All went well until we reached a marsh which gave us great trouble to get through. When we did get through, our barrage had shifted ahead about a mile and we had to make pace to catch it. About 11 a.m. we got to our second objective and remained there until 4 p.m., when we had to retreat, [. . .] It was only the will of God that got me through, for machine gun bullets and shrapnel were flying everywhere.
    Jim’s active war service came to an end at 2 a.m. on 30 May 1918, when, in the words of his journal, he ‘stopped a bomb from the Fatherland and got wounded in both legs’. The shell had fallen at his feet, blowing him upwards and killing the men around him.
    By the time I knew him, Jim was a wry, frail old man whose memory was on the blink. He was reticent on the subject of his war experience, but I do remember one conversation that took place when I was around nine years old. I asked him whether the men who fought in the war were scared or keen to get into the fight. He replied that some were scared and some were keen. Did the keen ones fight better than the scared ones, I asked. ‘No,’ said Jim. ‘It was the keen ones who shat themselves first.’ I was deeply impressed by this reply and puzzled over it – especially the word ‘first’ – for some time.
    The horror of this remote conflict still commands our attention. But its mystery lies elsewhere, in the obscure and convoluted events that made such carnage possible. In exploring these, I have accumulated more intellectual debts than I can possibly repay. Conversations with Daniel Anders, Margaret Lavinia Anderson, Chris Bayly, Tim Blanning, Konstantin Bosch, Richard Bosworth, Annabel Brett, Mark Cornwall, Richard Drayton, Richard Evans, Robert Evans, Niall Ferguson, Isabel V. Hull, Alan Kramer, Günther Kronenbitter, Michael Ledger-Lomas, Dominic Lieven, James Mackenzie, Alois Maderspacher, Mark Migotti, Annika Mombauer, Frank Lorenz Müller, William Mulligan, Paul Munro, Paul Robinson, Ulinka Rublack, James Sheehan, Brendan Simms, Robert Tombs and Adam Tooze have helped me to sharpen arguments. Ira Katznelson provided advice on decision theory; Andrew Preston on adversarial structures in the making of foreign policy; Holger Afflerbach on the Riezler diaries, the Triple Alliance and finer details of German policy in the July Crisis; Keith Jeffery on Henry Wilson; John Röhl on Kaiser Wilhelm II. Hartmut Pogge von Strandmann drew my attention to the little-known but informative memoirs of his relative Basil Strandmann, who was the Russian chargé d’affaires in Belgrade when war broke out in 1914. Keith Neilson shared an unpublished study of the decision-makers at the apex of