In the end, the central question that remained was what did American intelligence and law enforcement know and what did they ignore? What mistakes were made along the way on the ground by police, FBI and CIA, and in Washington and state capitals by policy makers? While hunting for those answers, there were unexpected discoveries about some American allies, and what they might have known, and not told anyone, before 9/11. The result is a far more infuriating book than originally expected. The failure to have prevented 9/11 was a systematic one. It is not just that investigators failed to get a lucky break early on, nor is it really even dependent on a series of blunders in the immediate run-up to the attack. The seeds for failure were sown repeatedly in almost twenty years of fumbled investigations and misplaced priorities. After a while, the revelations of ineptitude presented in this book no longer cause surprise, but only anger.
