What effect did personality and circumstance have on US foreign policy during World War II? This incisive account of US envoys residing in the major belligerent countries – Japan, Germany, Italy, China, France, Great Britain, USSR – highlights the fascinating role played by such diplomats as Joseph Grew, William Dodd, William Bullitt, Joseph Kennedy and W. Averell Harriman. Between Hitler's 1933 ascent to power and the 1945 bombing of Nagasaki, US ambassadors sculpted formal policy – occasionally deliberately, other times inadvertently – giving shape and meaning not always intended by Franklin D. Roosevelt or predicted by his principal advisors. From appeasement to the Holocaust and the onset of the Cold War, David Mayers examines the complicated interaction between policy, as conceived in Washington, and implementation on the ground in Europe and Asia. By so doing, he also sheds needed light on the fragility, ambiguities and enduring urgency of diplomacy and its crucial function in international politics.