In the years since the terrorist attacks of 9/11, government officials, industry experts, and interested citizens have sought to understand what happened, why it happened, and how we can prevent anything similar from ever happening again. Now, in four volumes, readers and researchers can read for themselves the complete, unabridged testimony of the hearings held by the National Commission on Terrorist Attacks Upon the United States, and draw their own conclusions. Each of the twelve hearings is summarized, as is each person's testimony, making it easy to find relevant passages. Specific coverage of each hearing includes a summary of remarks made and issues raised during the hearings and in official statements, biographies of the witnesses testifying before the commission, and official statements filed by key witnesses.