The Forgotten 500 – Gregory A. Freeman
This book documents the history of Operation Halyard, the greatest rescue mission of World War II. The achievement is little known today because US and UK politics kept it classified for 60 years. It was so secret that Yugoslavian General Mihailovich, who protected our downed airmen from the Nazis until they could be rescued, was secretly awarded the Legion of Merit for his service by President Truman but never even told. The award was finally presented to his daughter in 2005.
During the war the allies repeatedly bombed the major Axis oil refining facilities in Ploesti, Romania. Because those facilities provided a third of the fuel that powered the Nazi war machine they were a prime target for bombing raids. For that same reason they were heavily defended by the Germans. The result was literally scores of allied bombers were shot down. Many crashed in Yugoslavia with as many as 10 airmen bailing out of each.
Between August and December of 1944 the Office of Strategic Services (OSS), the forerunner of the Central Intelligence Agency, with support of the 15th Air Force rescued 512 downed airmen from German occupied territory in Yugoslavia with no loss of American lives. In retrospect the achievement seems like a miracle.