After working through it, I note that the book is a winner of the 2007 Pulitzer Prize for general nonfiction. So I'll just add my endorsement to that one. Lawrence Wright continues to cover the topic in his work for the New Yorker.
I've read a large number of books trying to understand some of the culture, background, etc of the situation I was working through during my year in Iraq, but had never carefully studied bin Laden and/or Afghanistan. I'll soon be "covering down" on a rear detachment command for a unit that is deploying to Afghanistan in the near future, one of two battalions within our brigade, so I have wanted to get a better sense of the big picture of what they are moving into- not that the text would give me any insight into what their day to day activities would look like (one engineer battalion, one MP battalion).
In any case, I was impressed with the level of detail in the text, and it felt very consistent with my experiences during my year in Iraq in trying to understand the motivations and cultural practices, expectations, etc of those with whom I worked or those that were trying to kill me and others like me.
I had one thought repeatedly come to me as I read and contemplated our engagements in Afghanistan to date. We really seem to be taking a broad and blunt instrument approach when it appears to me that the most effective approach would be more targeted and surgical. I can't profess to fully understand our mission and strategy right now, so it may be that the approach is completely aligned with the mission and strategy, in which case I'd suggest that we need to do a better job of communicating the mission and strategy to the general public.
In any case, a great book if you'd like to study the "how did it get to this?" question, and get some insight into the backgrounds of bin Laden and Zawahiri. Additionally, some interesting profiles of the U.S. folks that were trying to get in front of them, their ignored warnings and failed attempts to work through the bureaucratic infighting between CIA and FBI.