Though largely invisible in histories of the First World War, over 5,50,000 men in the ranks of the Indian army were non-combatants. From the porters, stevedores and construction workers in the Coolie Corps to those who maintained supply lines and removed the wounded from the battlefield, Radhika Singha recovers the story of this unacknowledged service. The labour regimes built on the backs of these 'coolies' sustained the military infrastructure of empire; their deployment in interregional arenas bent to the demands of global war. Viewed as racially subordinate and subject to 'non-martial' caste designations, they fought back against their status, using the warring powers' need for manpower as leverage to challenge traditional service hierarchies and wage differentials. The Coolie's Great War views that global conflict through the lens of Indian labour, constructing a distinct geography of the war-from tribal settlements and colonial jails, beyond India's frontiers, to the battlefronts of France and Mesopotamia.