The 44-year-old Bin Laden, as you probably know, is one of 50 children of a Saudi billionaire. (He made his fortune in construction. Among his projects: the tallest skyscraper in the Middle East.) After what seems to have been a playboy youth—drinking and womanizing in Lebanon—Bin Laden was radicalized in his early 20s, first by university professors, then by the Russian invasion of Afghanistan. He became an ardent believer in the Islamic struggle against infidels. During the Afghan war, Bin Laden used his own vast fortune (estimated at $250 million, but no one really knows) and money raised from Gulf Arabs to fund the mujahideen. He may or may not have fought himself, but he certainly recruited thousands of young Muslims from all over the Middle East to the cause.

Since the early '90s, Bin Laden has run al-Qaida ("The Base"), which CNN's Peter Bergen, author of the forthcoming Holy War, Inc., describes as a kind of "holding company" for Islamic militants. According to Bergen, Bin Laden has an inner circle of several hundred followers who have sworn him loyalty oaths. Several thousand men, perhaps as many as 10,000, have trained as soldiers and terrorists in Bin Laden's camps in Afghanistan and Sudan. These men populate and run militant Islamic groups in almost every country with a significant Muslim population, everywhere from Bosnia to Algeria to Chechnya to Indonesia. Bin Laden has been sheltered by the Taliban since Sudan expelled him in 1996. He has given the Taliban millions of dollars in aid.

It is not clear how much control Bin Laden has over his followers or over the acts of terror attributed to him. The best guesses are that Bin Laden has financed most if not all of these terrorist acts, and that his top aides had some kind of operational control over them.