Systematic account of force employment’s role and how this account holds up under rigorous, multi-method testing. The results challenge a wide variety of standard views, from current expectations for a revolution in military affairs, to mainstream scholarship in international relations, and orthodox interpretations of modern military history. The author argues that force employment is central to modern war, and has become increasingly important since 1900 as the key to surviving ever more lethal weaponry. Technological change produces opposite effects depending on how forces are employed; to focus only on materiel is thus to risk major error—with serious consequences for both policy and scholarship.