Second-Generation Warfare (2GW) marks the moment when the rational order of pre-industrial battle gave way to the mechanised chaos of modernity. Emerging from the fiscal-military state’s transformation into the industrial state, 2GW fused bureaucratic precision with technological lethality, producing wars where command became procedural and destruction systemic. Anchored in the First World War’s vast apparatus of trenches, telegraphs, and artillery, this chapter examines how firepower replaced manoeuvre and attrition replaced strategy, recasting both the ethics and epistemology of war. Drawing on historical analyses by Tilly, Keegan, and van Creveld, it traces how railways, communication networks, and mass production reshaped command tempo and political legitimacy. The case studies of the Marne, Verdun, and the Somme illustrate the paradox of progress—how innovation promised mastery but delivered moral rupture. Situating 2GW within the book’s larger genealogy, the chapter reveals how industrial warfare mechanised cognition, eroded agency, and foreshadowed the algorithmic determinism of later generations. Ultimately, it argues that 2GW is both a historical formation and an ethical warning: the moment when human ingenuity, stripped of restraint, turned precision into catastrophe.