CAMERA MARTYRS OF VIETNAM: From the series Unsung Heroes on the History Channel. By the end of the Vietnam war, 135 photojournalists had died while picturing a story that was sadder than words could describe. They died with violence, and they came from both sides, from no sides, and from a dozen countries. They were professionals, amateurs, soldiers and adventurers. All they had in common were cameras, guts, and professional brilliance. But beyond a string of Pulitzer Prizes, there was no memorial to these unsung heroes until a group of their surviving comrades collaborated on an astonishing book called, appropriately, Requiem.