Analyzing the special chemistry of life in Number 10 Downing Street, Peter Hennessy scrutinizes what the Prime Minister actually does and the way that Cabinet government is run. He draws on unprecedented access to many of the leading politicians and also recently declassified, electrifying archival material. He illuminates Prime Ministerial attitudes towards, and authority over, such topics as nuclear weapons policy, the planning and waging of war, and foreign crises from Suez to the Falklands. He concludes with controversial assessments of each Prime Minister's performance and outlines a new profile of the premiership for the 4th century.