The first history and definitive history of the Cabinet Office, one of Britain's most important political institutions. The story of the Cabinet Office, created in the depths of the Great War in December 1916, goes to the very heart of the British state over the last 100 years. It has been at the centre of everything - war, intelligence, spy scandals, disputed elections, political crises, changes of Prime Minister. The eleven Cabinet Secretaries have been Britain's true 'men of secrets', guiding and shaping their political masters, the Prime Ministers, and keeping the British state stable and safe. Written with unparalleled access to documents and personnel, this lavishly illustrated history will give readers the definitive inside account of what has really gone over the last 100 years.