This volume consists of a book and downloadable resources containing a facsimile collection of diplomatic documents covering British reactions to critical developments regarding Berlin, its quadripartite administration, and role in the Cold War during the crises of 1948-49, 1959-61 and 1988-90. These events were each set within very different international contexts, but four interrelated themes are nevertheless common to each of the three chapters of the volume: the British Government’s insistence, in conjunction with the Americans and the French, on upholding and safeguarding the rights of the four occupying powers in Berlin; British concerns with broader matters of military security in Western Europe as a whole and Germany in particular; the interaction of the four occupying powers with one another; and the questions raised by demographic change, especially population movements from east to west. All of the documents dealing with the events of 1989-90 fall within the UK’s 30-year rule and are therefore not yet in the public domain.