Lt. Cmdr. Robert Shumaker, shown here at the time of his capture in February 1965. He was the second U.S. Navy pilot shot down in North Vietnam. He and an Air Force officer, Capt. Carlyle Harris, created the “tap code,” which became a lifeline to American POWs (reprinted from The Battle Behind Bars, Naval Historical Foundation/Naval History and Heritage Command [NHHC], Washington, DC, 2010).