Since the 1998 Good Friday Agreement a more relaxed political atmosphere has encouraged participants in the conflict to talk about their experiences, while more archival sources have opened up. This book draws upon an unprecedented array of primary sources, including papers on policy-making in London (cabinet, MOD, NIO and Foreign Office files) and military records created by HQNI, brigade staffs and battalions. Regimental archives were consulted in addition to non-military sources, such as the papers of journalists, politicians, clergymen and lobby groups. Records from NATO’s archive were scrutinised to assess whether the army was under pressure to limit the forces sent to Northern Ireland. As with all historical research, there are limits to the available sources. At the time of writing, there were just over 900 files covering the years 1966 to 1975 listed on the National Archives catalogue as closed, or retained by a government department, that had the phrase ‘Northern Ireland’ in the title. There are many hundreds more unavailable with different file titles yet likely to contain relevant information.