The terrorists who have succeeded in carrying out spectacular attacks against Western targets in the past have been college-educated, technically proficient men who are capable of manufacturing and deploying chemical, radiological, and biological weapons. Al Qaeda attracts the kind of highly educated men who one day might be able to pull off such an attack.

Most Muslims don't want to live in some Taliban-style utopia, which is what bin Laden and allied groups are offering.

Why should Americans care about the Nazi back story in World War II? If you don't have the Nazi back story in World War II, World War II is simply not comprehensible.

If you don't understand what al Qaeda was trying to do on 9/11, if you don't have a sense of who Osama bin Laden is as a person, if you don't have a sense of what al Qaeda, the organization, was on 9/11, 9/11 appears to be more or less inexplicable.

Bin Laden comes out of a business background - he studied public administration and economics at university, and he worked for his family company, which was obviously a rather successful enterprise.

I've interviewed multiple people who know bin Laden... who tend to have a universal picture of what he's like, which is: modest, retiring, unassuming, kind of thoughtful - lots of things that don't fit with a mass murderer, which he is as well.

Often it is important to listen to what people aren't saying.