At the very heart of the special relationship between Britain and the United States lies an extraordinary sharing of secret intelligence. This unique alliance was built during the Second World War thanks largely to the close relationship forged between the United States' President Franklin D. Roosevelt and Britain's wartime Prime Minister Winston Churchill. As the two leaders communicated almost daily by secret telegram and telephone, personal meetings and messages through intermediaries to develop an unprecedented level of trust, so their respective intelligences agencies began to share their closely guarded secrets in the fields of code breaking, human intelligence, and secret operations. Yet simultaneously each national leader sought to protect and advance his own country's interests and thus on occasion withhold rather than share his secrets. How Roosevelt and Churchill managed this delicate task and yet still laid the foundations of the closest intelligence relationship between two nations the world has ever known lies at the heart of this gripping narrative. "Stafford is a superb researcher and has a feel for when 'secret' means 'significant' and when it did not... This fascinating book is, among other things, a useful reminder of how complicated the Grand Alliance actually was." - New York Times "Stafford has the precious gift of making technical subjects easy to follow... This is most readable history." - The Times "An intriguing book which makes a very good read." - Irish Independent