more lethal. before he was captured, when he first joined al qaeda, they were killing dozens at a time. as soon as he got into senior leadership, they began killing hundreds and then thousands at a time. after he was captured in march 2003, the lethality of al qaeda fell. this is a guy that really mattered and understanding him is about understanding the future of the war on terror. now that bin laden is dead, this is what we have to fear, the terrorist entrepreneurs like khalid sheikh mohammed. when did you start this book? about two years ago. the question had been on my mind since 9/11, how do people become terrorists. educated, successful people at the top of their society. 2/3 of al qaeda are college graduates with advanced degrees so they re the best from their society from an educational point of view. how do these people become transformed, what series of choices do they make to become terrorists, to kill hundreds of thousands of other people. that was the questio