Use of Mines in Trench Warfare (From the French School of St. Cyr) is a comprehensive military manual that delves into the strategic and technical aspects of mining operations during trench warfare, as practiced and taught by the renowned French military academy, St. Cyr. Originally published during the First World War, this book provides an in-depth exploration of the theory, planning, and execution of subterranean warfare, a critical yet often overlooked component of the conflict on the Western Front. The manual begins by outlining the historical context and evolution of mining in military operations, emphasizing its resurgence as a decisive tactic in the static, entrenched battlefields of World War I. It details the organization and responsibilities of specialized mining units, the selection and preparation of suitable terrain, and the construction of galleries, shafts, and listening posts. The text meticulously describes the tools, materials, and safety measures required for effective and secure mining, as well as the methods for detecting and countering enemy mining activities. A significant portion of the book is dedicated to the practical aspects of mine placement, including the calculation of charges, the use of explosives, and the timing and coordination of detonations to maximize their impact on enemy fortifications and troop concentrations. The manual also addresses the psychological and tactical effects of mining, such as undermining enemy morale and disrupting defensive positions. Illustrated with diagrams and technical drawings, Use of Mines in Trench Warfare serves as both a training guide for military engineers and a historical document, offering valuable insights into the ingenuity and resourcefulness required to wage war beneath the surface. It stands as a testament to the scientific and methodical approach adopted by the French military, providing modern readers with a detailed understanding of one of the most complex and perilous aspects of trench warfare.