On September 11, 2001, nearly 3,000 people died in terrorist attacks upon the United States. Hijacked planes struck the World Trade Center and the Pentagon, while an additional plane crashed into the fields of Pennsylvania. This series of events resulted in the single largest loss of life from enemy attack on U.S. soil.

The National Commission on Terrorist Attacks Upon the United States, also known as the 9/11 Commission, was created by congressional legislation and the signature of President George W. Bush in late 2002. This independent, bipartisan commission had the task of producing a full and complete account of the circumstances surrounding the attack, including preparedness and immediate response, and providing recommendations designed to guard against future attacks.

The 9/11 Commission released their final report to the public on July 22, 2004. During the course of the Commission's 20-month investigation, the 10 commissioners and 80 staff members conducted more than 1300 interviews in 10 countries and reviewed more than 2 million documents. In the 17 days of public hearings, the commissioners heard testimony from 140 federal, state, and local officials, and private sector experts.

The Commission was composed of Chair Thomas H. Kean, Vice Chair Lee H. Hamilton, and Commissioners Richard Ben-Veniste, Fred F. Fielding, Jamie S. Gorelick, Slade Gorton, Bob Kerrey, John F. Lehman, Timothy J. Roemer, and James R. Thompson.