Who were the shadow agents of Renaissance war? In this pioneering collection of essays scholars use new archival evidence and other sources, including literature, artworks, and other non-textual material, to uncover those men, women, children and other animals who sustained war by means of their preparatory, auxiliary, infrastructural, or supplementary labour. These shadow agents worked in the zone between visibility and invisibility, often moving between civilians and soldiers, and their labour was frequently forced. This volume engages with a range of important debates including: the relationship between war and state formation; the ‘military revolution’ or transformation of early modern military force; the nature of human and non-human agency; gender and war; civilian protection and expulsion; and espionage and diplomacy. The focus of the volume is on Italy, but it includes studies of France and England, and the editors place these themes in a broader European context with the aim of supporting and stimulating research in this field.