In the popular imagination MI5, or the Security Service, is know chiefly as the branch of the British state responsible for chasing down those who pose a threat to the country's national security—from Nazi fifth columnists during the Second World War, to Soviet spies during the Cold War and today's domestic extremists. Yet, aided by the release of official documents to the National Archives, David Caute argues in this radical and revelatory history of the Security Service in the twentieth century, suspicion often fell on those who posed no threat to national security. Instead, this 'other history' of MI5, ignored in official accounts, was often as not fuelled by the political prejudices of MI5's personnel, and involved a huge programme of surveillance against anyone who dared question the status quo. Caute, a prominent historian and expert on the history of the Cold War, tells the story of the massive state operation to track the activities of a range of journalists, academics, scientists, filmmakers, writers and others who, during the twentieth century, the Security Service perceived as a threat to the national interest. Those who were tracked include such prominent figures as Kingsley Amis, George Orwell, Doris Lessing, John Berger, Benjamin Britten, Eric Hobsbawm, Michael Foot, Harriet Harman, and others.