The Boer War that raged across present-day South Africa from 1899 to 1902 was Britain’s costliest and bloodiest war in the century between 1815 and 1914. It was arguably the most humiliating of the nation’s colonial history. The Boer conflict was a dirty war with atrocities committed on both sides. The conflict also witnessed the advent of key military innovations on a large scale. Repeating rifles and machine guns turned the strategic balance in favor of defense, a trend that would see its full, devastating manifestation in the muddy trenches of France a dozen years later. The commander of Britain’s military forces in the campaign, Lord Kitchener, was also one of the most controversial figures of his time. He succeeded in waging a counterguerrilla campaign against a hard-fighting enemy, despite numerous tactical defeats and an outraged opposition at home. The Boer War is also instructive for our study of the American experience in irregular warfare given that it provides an important comparison of how another imperial power fared in similar circumstances. At the very time that the British were mired in the Boer War, U.S. political and military forces were attempting to quell an insurgency and “nation-build” in the Philippines.