nelly lahoud focused on 6,000 pages of them, for her book, "the bin laden papers." so, you were creating kind of a narrative based on all of the documents? >> lahoud: and you couldn't do it any other way. you couldn't have a division of labor where several people will take it on, because they're all so connected. vague references in one letter can only be explained if you looked at several other letters. so really, to get a grasp of what was really going on, you really need to be able to have read them all together. >> alfonsi: letters were the only way osama bin laden communicated with al-qaeda associates for nearly a decade, because he was trying to evade capture. bin laden had television in his compound, but didn't have access to the internet, or phone, so everything was written by hand or on computers, and encrypted on flash drives that were given to couriers to deliver. all the letters were backed up on hard drives. >> lahoud: we see in the letters diminutive bin laden, somebody who is very different from this powerful figure that we were reading about daily in