The five volumes of the Mark Sturgis diaries provide a source for Anglo-Irish history during the final stages of the Irish revolution between July 1920 and February 1922. Sturgis was a leading British civil servant seconded to Dublin Castle in the summer of 1920 as a consequence of the radical administrative reforms implemented at the time. In effect he served as the main assistant to Sir John Anderson, the joint under-secretary and effective leader of the administration. Sturgis played a key role in decisions made in the final stages of the Anglo-Irish War and was actively involved in peace negotiations. The volumes contain descriptions of life in Dublin Castle and of Sturgis' liaison work with London. There are portrayals of leading figures of the period on both the British and Irish sides. The diaries are valuable not only as a historical source, but also as social history with much revolving around Sturgis' affection for the world of horses and country houses. They give an insight into the relations between civil servants and politicians at a time when civil servants were to a large extent in control of British policy in Ireland.