The Abors were an Assam tribe inhabiting a tract of hill country on the north-east frontier of India, first visited by the English in 1826. Much of the area was terra incognita and problems arose connected with the Indo-Chinese and Indo-Tibetan borders. It was the murder, in 1911, by the Abors of the British Assistant Political officer, Mr Williamson, and his colleague Dr Gregorson and nearly all their party of followers while they were touring the Tibetan border area that was the immediate cause of the war. The punitive expeditionary force was composed of Indian Army troops (no British units) and operations lasted from October 1911 to April 1912. The narrative begins with an account of the political events leading up to the expedition, describes the terrain and the tribes and then goes on to relate the murder and discuss the plans for the expedition which was commanded by Major-General Sir H Bower, GOC Assam Brigade. There are an unusually high number of appendices (37), partly explained by the brief preface to the effect that because this was the first miiitary expedition in the area "it has been considered desirable to attach to the history, as appendices, somewhat full extracts from departmental and other reports referring to details of organization, etc., peculiar to the country." But the account of the operations is well suported by more appendices giving a wealth of detail on all aspects of the Force involved, beginning with orders for the organization of the Abor Expeditionary Force, issued by the Chief of the General Staff. There are charts, tables, reports on engineering operations, medical history of the expedition, work of followers and much more beside.