During his time as a Captain in the US Army, John Giannaris lead an all Greek unit, GROUP II, behind German lines in Greece during the summer of 1944. GROUP II, a twenty-two man guerilla outfit, and their fearless leader, Captain Giannaris, successfully orchestrated the withdrawal of German troops from the Valley of Lamia in Greece. In September of 1944, Captain Giannaris stepped on a German Teller mine, which nearly ended his life. After the removal of some 300 pieces of shrapnel and two and a half years of recuperation, Captain Giannaris was discharged from the Army. He later published the book Yannis which includes many details about his mission in World War II.