Tunnel Warfare explores the often-overlooked world of subterranean conflict, revealing its profound impact on military history from ancient sieges to modern asymmetrical warfare. The book examines how tunneling techniques have evolved, from basic hand-dug passages used to undermine city walls to complex, engineered networks employed by insurgents and terrorist groups. It also highlights the psychological toll on soldiers and civilians facing the unique terrors of fighting in the dark, where the enemy could be anywhere. This study provides a unique perspective by emphasizing the continuity and adaptability of tunnel warfare across different eras. Ethical considerations, such as the targeting of underground infrastructure, are also addressed. By drawing on primary sources and archaeological findings, the book traces the use of tunnels from antiquity, through the industrial revolution and into the age of modern insurgent warfare. It culminates by examining the future and ethics of subterranean combat, making it valuable to those interested in military history, strategy, and the evolving nature of conflict.