What emerged was an astonishing inside look at the day-to-day world of al-Qaeda, as managed by its top strategic planners—among them bin Laden, al-Zawahiri, Atef, Ramzi bin al-Shibh, and Khalid Sheikh Muhammad, all of whom were intimately involved in the planning of 9/11, and some of whom (bin Laden and al-Zawahiri) are still at large. The documents included budgets, training manuals for recruits, and scouting reports for international attacks, and they shed light on everything from personnel matters and petty bureaucratic sniping to theological discussions and debates about the merits of suicide operations. There were also video files, photographs, scanned documents, and Web pages, many of which, it became clear, were part of the group’s increasingly sophisticated efforts to conduct a global Internet-based publicity and recruitment effort.

The jihadis’ Kabul office employed a zealous manager—Ayman al-Zawahiri’s brother Muhammad, who maintained the computer’s files in a meticulous network of folders and subfolders that neatly laid out the group’s organizational structure and strategic concerns. (Muhammad’s system fell apart after he was arrested in 2000 in Dubai and extradited to Egypt.) The files not only provided critical active intelligence about the group’s plans and methods at the time (including the first leads about the shoe bomber Richard Reid, who had yet to attempt his attack) but also, in a fragmentary way, revealed a road map of al-Qaeda’s progress toward 9/11. Considered as a whole, the trove of material on the computer represents what is surely the fullest sociological profile of al-Qaeda ever to be made public.

Perhaps one of the most important insights to emerge from the computer is that 9/11 sprang not so much from al-Qaeda’s strengths as from its weaknesses. The computer did not reveal any links to Iraq or any other deep-pocketed government; amid the group’s penury the members fell to bitter infighting. The blow against the United States was meant to put an end to the internal rivalries, which are manifest in vitriolic memos between Kabul and cells abroad. Al-Qaeda’s leaders worried about a military response from the United States, but in such a response they spied opportunity: they had fought the Soviet Union in Afghanistan, and they fondly remembered that war as a galvanizing experience, an event that roused the indifferent of the Arab world to fight and win against a technologically superior Western infidel. The jihadis expected the United States, like the Soviet Union, to be a clumsy opponent. Afghanistan would again become a slowly filling graveyard for the imperial ambitions of a superpower.

Like the early Russian anarchists who wrote some of the most persuasive tracts on the uses of terror, al-Qaeda understood that its attacks would not lead to a quick collapse of the great powers. Rather, its aim was to tempt the powers to strike back in a way that would create sympathy for the terrorists. Al-Qaeda has so far gained little from the ground war in Afghanistan; the conflict in Iraq, closer to the center of the Arab world, is potentially more fruitful. As Arab resentment against the United States spreads, al-Qaeda may look less like a tightly knit terror group and more like a mass movement. And as the group develops synergy in working with other groups branded by the United States as enemies (in Iraq, the Israeli-occupied territories, Kashmir, the Mindanao Peninsula, and Chechnya, to name a few places), one wonders if the United States is indeed playing the role written for it on the computer.