They went in as confident young warriors. They came out as battle-scarred veterans, POW camp survivors . . . or worse. The Army Air Corps’ 27th Bombardment Group arrived in the Philippines in November 1941 with 1,209 men; one year later, only 20 returned to the United States. The Japanese attacked the Philippines on the same morning as Pearl Harbor and invaded soon after. Allied air routes back to the Philippines were soon cut, forcing pilots to fight their air war from bases in Java, Australia, and New Guinea. The men on Bataan were eventually taken prisoner and forced into the infamous Death March. The 27th and other such units were pivotal in delaying the Japanese timetable for conquest. If not for these units, some have suggested, the Allied offensive in the Pacific might have started in Hawaii or even California instead of New Guinea and the surrounding islands. Based largely on primary materials, including a fifty-nine-page report written by the surviving unit members in September 1942, Operation PLUM (from the code name for the U.S. Army in the Philippines) gives an account of the 27th Bombardment Group and, through it, the opening months of the Pacific theater. Military historians and readers interested in World War II will appreciate the rich perspective presented in Operation PLUM