Pt. 1. The events of 9/11. Flights 11 and 175: how could the hijackers' missions have succeeded? -- Flight 77: was it really the aircraft that struck the Pentagon? -- Flight 93: was it the one flight that was shot down -- The President's behavior: why did he act as he did? -- Pt. 2. The larger context. Did US officials have advance information about 9/11? -- Did US officials obstruct investigations prior to 9/11? -- Did US officials have reasons for allowing 9/11? -- Did US officials block captures and investigations after 9/11? -- Pt. 3. Conclusion. Is complicity by US officials the best explanation? -- The need for a full investigation.