In 1944, Secretary of War Henry L. Stimson, knowing that high-ranking members of the military had falsely testified before the various bodies investigating the attack on Pearl Harbor, selected a then-unknown major by the name of Henry C. Clausen to undertake a new investigation. From November 1944 to September 1945, Clausen traveled more than 55,000 miles and interviewed over a hundred U.S. and British Army, Navy, and civilian personnel. He was given the authority to go anywhere and question anyone under oath, from enlisted personnel right up to George. C. Marshall, the Chief of Staff. He ultimately presented an 800-page report to Stimson -- a report that revealed a massive operational failure by the United States to use the priceless signals intelligence that it had obtained months before Pearl Harbor. Pearl Harbor is the "final judgement" -- the story behind Clausen's investigation and a blistering account of his conclusions.