The Third Afghan War has some claim to be the least-known of all British imperial conflicts - even among military historians. But this was no mere border skirmish: although the fighting lasted barely a month and British casualties were slight in comparison to those suffered in the First World War, the conflict spanned the whole North-West Frontier of India and was important enough to involve the mobilisation of 350,000 British soldiers. Unlike previous conflict in Afghanistan, this was a war of Afghan aggression, which Sir Hamilton Grant, a leading participant, characterised as: 'the most meaningless, crazy and unnecessary war in history.' In the aftermath of the First World War, the Afghan invasion of India in May 1919 and the subsequent fighting along the frontier aroused little interest outside of India, and it has since attracted little scholarly attention. Yet it deployed in India for the first time the full range of modern military technology. Robson clearly outlines the context in which the conflict took place, detailing the uneasy peace between Britain and Afghanistan after the First and Second Anglo-Afghan wars and relations with Waziristan from 1849 to 1919. Illustrated with maps and contemporary photographs, "Crisis on the Frontier" is the definitive account of this important and fascinating chapter in British history.