The premise of James Robert’s book is fascinating and intriguing. His study has two objectives. Firstly, to examine what British infantrymen did during battle in the Great War, especially in relation to fighting and killing the enemy. Secondly, to gauge the morale of the soldiers during major battles of the conflict. The 19th (Western) Infantry Division is used as a case study for his investigation.
He also puts forward a controversial and interesting argument that ‘a significant number of the division’s infantrymen took no active part in combat…[v]ery few soldiers were either willing or able to fight…the enemy’. His argument is that, citing Thomas Paine, ‘man is essentially pacifistic and desirous of living in harmony with his fellow Man’.
Unfortunately, Robert’s book does not convincingly sustain his argument. The publication has five problems that handicap it: Robert’s reliance on Samuel Marshall’s work, the paucity of recent secondary literature, his methodology for measuring morale, the use of limited sources and frequent statements that are unsupported by evidence.
The first challenge is Robert’s use of the work of Samuel Attwood Lynam Marshall. He draws on Marshall’s work to support his argument that man is essentially a pacifist. Marshall controversially found that during the Second World War, only a quarter of US infantry soldiers fired their weapon in combat. The reason for hesitancy was that US soldiers were programmed by society not to kill. Marshall’s work has been dismissed through poor methodology and falsification. Though Roberts acknowledges Marshall’s critics, such as Roger Spiller, he dismisses them believing they have a ‘reluctance…countenance the idea that realising killing in combat is anything other than a problem of discipline and weapons competency’. For him, Marshall’s views are ‘axiomatic’.
If men are naturally pacific, Robert’s does not explain his reasoning for this contention. For example, he makes no attempt to say how Edwardian society may have shaped the civilian soldier into a peace loving individual.
Added to this, he argues that teams of men operating ‘distance’ crewed weapons, such as machine guns, were more likely to kill because of ‘depersonalised aggression, and distance, automation and teamwork’ which ‘sanitised the act’ of killing.
He also asserts that officers were often important to lead and persuade their men to fire or kill the enemy. However, he does not explain why this is so. If, as he states, man’s nature is universal and ‘essentially pacifistic’, why do officers or men operating a machine gun not share this human nature with other combatants?
The second problem is Robert’s use of secondary literature. His 2017 book is based on his PhD thesis that was awarded in 2004. However, he cites no scholarship published after 2004; it appears that the book maybe is a nearly complete facsimile of his thesis. This is a pity as much relevant scholarship has been produced on morale and motivation in the years between 2004 and 2017. Reference to Anthony King’s 2012 book, The Combat Soldier, could have provided the basis for a more solid defence Marshall and his ideas
The third issue is Robert’s methodology. For example, in his attempt to measure morale of the 19th Division, he uses two quantitative methods. The first is the level of casualties, in particular, ‘number of casualties individual battalions were willing to suffer before sacrificing the objective to safety’. Essentially, this is contradictory saying that a unit’s willingness to die was an indication of its willingness to fight. How this measure is used to assess morale is difficult to understand and not explained.
His second measure are courts martial statistics. These are a more reliable method of assessing morale. However, he gives some court martial statistics in random chapters but offers no comparative data against which their significance can be assessed.
The fourth challenge is the limited use of primary sources. Roberts refers mainly to official war diaries kept by units in the 19th Division. He rejects the letters of Great War combatant because the Great War does not have collections of ‘uncensored letters’ that the US civil war has. He dismisses veteran memoirs as there are issues with individuals ‘recollection’ and few mention ‘killing or maiming’ in their memoirs. Finally, the content of war diaries was set down by GHQ and they were open to far fewer falsehoods than other sources. This is a very odd approach given this book is about individual motivation in battle and personal letters, diaries and memoirs would be a key source. Also, a significant minority of Great War memoirs, letters and diaries give a great deal of detail of killing.
The methodological challenges have led to a book that can be erratic and confusing at times. For example, Roberts questioned whether machine gunners ‘needed to be more willing or able to kill than his fellow riflemen.’  Another example is his treatment of the 19th Division’s attack Menin Road Ridge in September 1917. He says that the offensive stalled because ‘sight or notion of one-in-three of their comrades being hit was compelling infantrymen to sacrifice the objective for safety’. He does not explain how the unit collectively calculated the ratio of casualties during battle and why this would lead a unit to seek safety rather than its objective.
Some of the deductions he reaches are statements of the obvious. The lesson he drew from the 19th Division time at Messines Ridge in June 1917 was that an ‘overwhelming artillery superiority could deliver success at a cost in lives that the infantry could sustain – both materially and morally. Platoon tactics could provide the advantage in localised ‘infantry vs infantry’ conflicts. But in the infantry were left to fight along to fight a ‘infantry versus machine guns’ or ‘infantry versus artillery battle’ the outcome was just as it had in 1915 and 1916 – a bloody failure’.
Finally, some of his conclusions can seem contradictory. For example, on page 258, he argues that battlefield pacifism was both common and not. At one point, he asserts it was ‘rarely widespread but a common occurrence’. Further down the page he states the opposite that ‘many’ of the 19th’s infantry remained ‘committed non-firers’ and the ‘more pacifistic’ were in the majority’.
The disappointing aspect of this book is that Robert’s appears to be onto something and he does find evidence to suggest that soldiers during attacks did go ‘missing’ and some men in battle did not participate in combat. This is a phenomenon that would warrant further inquiry and has recently grabbed the attention of other scholars. However, methodological issues and the limiting the scope to one division means that the study does not sustain its argument or objectives. It is less an investigation into the phenomenon of non-firing by soldiers in battle and more of a narrative history of the 19th Division during the Great War.
 James Roberts, Killer Butterflies – Combat, Psychology and Morale in the British 19th (Western) Division 1915–18 (Solihull – Helion, 2017), p.xi.
 Ibid., p.xii.
 Ibid., p.xv.
 Ibid., p.xiii.
 Ibid., p.xiv.
 Ibid., p.xi.
 Samuel L.A. Marshall, Men Against Fire: The Problem of Battle Command in Future War (Peter Smith, 1978), pp.23, 42, 138.
 Roger J. Spiller, ‘S.L.A. Marshall and the Ratio of Fire’, JRUSI, 133 (Dec. 1988), pp.63-71; John Whiteclay Chambers II, ‘S.L.A. Marshall’s Men Against Fire: new evidence regarding fire ratios’, Parameters 33 (Autumn 1993), pp.113-121; Robert Engen, Canadians Under Fire: Infantry Effectiveness in the Second World War (Montreal & Kington: McGill-Queen’s University Press, 2009), pp.19-22, 146-149.
 Roberts, p.31.
 Ibid., p.30.
 Ibid., p.55.
 Ibid., p.169.
 Ibid., pp.182-183.
 For example Alexander Watson, Enduring the Great War. Combat, Morale, Collapse in the German and British Armies, 1914-1918 (Cambridge: CUP, 2008) and Jonathan Boff, Winning and Losing on the Western Front (Cambridge: CUP, 2014).
 Anthony King, The Combat Soldier (Oxford: OUP, 2019), pp.98-115.
 Roberts, p.49.
 Ibid., p.49.
 See Tim Bowman, Irish Regiments in the Great War, Morale and Discipline (Manchester MUP, 2003), p.18.
 Roberts, p.44.
 Ibid., p.43.
 Ibid., p.44.
 Ibid., pp.46-47.
 Ibid., p.46.
 Ibid., p.xi. See for examples of killing in memoirs and letters Tom Thorpe, ‘Why they enlisted, served and killed; the experience and motivation of Leicestershire servicemen during the Great War, Midland History, Vol.44 Issue 1 (May 2019), pp.85-106.
 Roberts, p.55.
 Ibid., p.178.
 Ibid., p.170.
 Ibid., p.258.
 Ibid., pp.61, 75
 See King, Combat Soldier and Gary Sheffield, ‘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, Volume 5, Issue 1 (July 2019).