Citizens of London, by Lynne Olson

Very interesting book about the Americans who were pushing for the United States to enter WWII while Britain was struggling to survive as the last European holdout against the Nazis. It focuses on Averell Harriman (not a particularly positive portrait of him), Edward R. Murrow, and Gil Winant, who is the most fascinating character in the book. Churchill and Roosevelt, meanwhile, come off as big egotistical babies. Crazily, all three of these American protagonists become so closely involved with the British wartime government that all of them had affairs with members of Churchill's family.