Ten days after the Nazis marched into Poland, on September 11, 1939, President Franklin D Roosevelt wrote for the first time to Winston Churchill, then First Lord of the Admiralty, proposing that he reply "with anything that you want me to know about." The extraordinary correspondence thus begun, which was kept secret from all but the leaders' closest advisors, continued throughout World War II, until the day Roosevelt died. The messages were entirely declassified only in 1972. The two men sent more than 1700 communications, an average of almost one message a day. The editors have chosen some 600, the most interesting and important letters from the entire correspondence, for inclusion here. In addition, they have provided generous annotation to supply the necessary context for the contemporary reader and to take advantage of the best and most recent scholarship on the war years.