Book excerpt: In 2003, Major William Edwards and Lt. Col. Robert P. Walters of the 165th Military Intelligence Battalion were given the near-impossible task of improving the U.S. Army's security posture at Abu Ghraib prison under unfathomable conditions. With input from officers who served with them, their candid firsthand accounts of life at the notorious prison reveal unpublished details of the human devastation that took place there, along with unexpected glimpses of humanity.