Marc Sageman was a CIA case officer in Afghanistan between 1987?89 and is now a forensic psychiatrist in Philadelphia. His book, Understanding Terror Networks, was published by the University of Pennsylvania Press earlier this year.
After the attacks on New York and Washington of September 11, 2002, Dr. Sageman noticed the lack of systematic data on the perpetrators, so he began to apply the principles of evidence-based medicine to terrorism research. He gathered terrorist biographies from various sources, relying most heavily on the records of various criminal trials. After matrixing approximately 400 biographies, Dr. Sageman began a social-network analysis of this group.
This Foreign Policy Research Institute article provides a summary of Dr. Sageman’s findings and conclusions. Inasmuch as the entire article is fascinating, I had a difficult time deciding which excerpts to pass along, but here are a few.
First, Dr. Sageman notes that the key period of development for the current radical Islamic fascists was the time in the late 1980’s and early 1990’s when their leadership gathered in Khartoum, Sudan to hatch their dream of indepedent “Salafi” states:

The Khartoum period is critical, because what these violent Salafists basically want to do is to create a Salafi state in a core Arab country. Salafi (from Salaf, ?ancient ones? or ?predecessors? in Arabic) is an emulation, an imitation of the mythical Muslim community that existed at the time of Mohammed and his companion, which Salafists believe was the only fair and just society that ever existed. A very small subset of Salafis, the disciples of Qutb, believe they cannot create this state peacefully through the ballot-box but have to use violence. The utopia they strive for is similar to most utopias in European thought of the nineteenth to the twentieth centuries, such as the communist classless society.

Moreover, Dr. Sageman points out that the background of the radical Islamic fascist leadership is similar to that of the “best and the brightest” of the societies from which they have emerged:

Most people think that terrorism comes from poverty, broken families, ignorance, immaturity, lack of family or occupational responsibilities, weak minds susceptible to brainwashing – the sociopath, the criminals, the religious fanatic, or, in this country, some believe they?re just plain evil.
Taking these perceived root causes in turn, three quarters of my sample came from the upper or middle class. The vast majority?90 percent?came from caring, intact families. Sixty-three percent had gone to college, as compared with the 5-6 percent that?s usual for the third world. These are the best and brightest of their societies in many ways.
Al Qaeda?s members are not the Palestinian fourteen-year- olds we see on the news, but join the jihad at the average age of 26. Three-quarters were professionals or semi- professionals. They are engineers, architects, and civil engineers, mostly scientists. Very few humanities are represented, and quite surprisingly very few had any background in religion. The natural sciences predominate. Bin Laden himself is a civil engineer, Zawahiri is a physician, Mohammed Atta was, of course, an architect; and a few members are military, such as Mohammed Ibrahim Makawi, who is supposedly the head of the military committee.

Mr. Sageman notes that there really is not one profile for a radical Islamic fascist:

So what?s in common? There?s really no profile, just similar trajectories to joining the jihad and that most of these men were upwardly and geographically mobile. Because they were the best and brightest, they were sent abroad to study. They came from moderately religious, caring, middle-class families. They?re skilled in computer technology. They spoke three, four, five, six languages. Most Americans don?t know Arabic; these men know two or three Western languages: German, French, English.
When they became homesick, they did what anyone would and tried to congregate with people like themselves, whom they would find at mosques. So they drifted towards the mosque, not because they were religious, but because they were seeking friends. They moved in together in apartments, in order to share the rent and also to eat together – they were mostly halal, those who observed the Muslim dietary laws, similar in some respects to the kosher laws of Judaism. Some argue that such laws help to bind a group together since observing them is something very difficult and more easily done in a group. A micro-culture develops that strengthens and absorbs the participants as a unit. This is a halal theory of terrorism, if you like.
These cliques, often in the vicinity of mosques that had a militant script advocating violence to overthrow the corrupt regimes, transformed alienated young Muslims into terrorists. It?s all really group dynamics. You cannot understand the 9/11 type of terrorism from individual characteristics. The suicide bombers in Spain are another perfect example. Seven terrorists sharing an apartment and one saying ?Tonight we?re all going to go, guys.? You can?t betray your friends, and so you go along. Individually, they probably would not have done it.

In fact, the lack of these social networks is one of the reasons why Dr. Sageman believes that another 9/11-type attack has not occurred in the United States:

Indeed, there are not that many terrorists in America. There have never been any sleeper cells. All the terrorists are fairly obvious. The FBI cases we see in the press tend to unravel. The Detroit group has been exonerated, and the prosecutor is now being prosecuted for malfeasance on the planted evidence. He allegedly knew exculpatory facts that he did not present to the defense. The only sleeper America has ever had in a century was Soviet Col. Rudolf Abel, who was arrested in the late 1950s and exchanged for Gary Powers, the U2 pilot. Eastern European countries did send sleepers to this country, men fully trained who ?go to sleep??lead normal lives?and then are activated to become fully operational. But they all became Americans.
In order to really sustain your motivation to do terrorism, you need the reinforcement of group dynamics. You need reinforcement from your family, your friends. This social movement was dependent on volunteers, and there are huge gaps worldwide on those volunteers. One of the gaps is the United States. This is one of two reasons we have not had a major terrorist operation in the United States since 9/11. The other is that we are far more vigilant. We have actually made coming to the U.S. far more difficult for potential terrorists since 2001.

But Dr. Sageman warns that the radical Islamic fascists have adapted and changed the way in which they will plan future attacks:

We hear that Al Qaeda plans its attacks for years and years. It may have before 9-11, but not anymore. Operatives in caves simply cannot communicate with people in the field. The network has been fairly well broken by our intelligence services. The network is now self-organized from the bottom up, and is very decentralized. With local initiative and flexibility, it?s very robust. True, two-thirds to three- quarters of the old leaders have been taken out, but that doesn?t mean that we?re home free. The network grows organically, like the Internet. We couldn?t have identified the Madrid culprits, because we wouldn?t have known of them until the first bomb exploded.
So in 2004, Al Qaeda has new leadership. In a way today?s operatives are far more aggressive and senseless than the earlier leaders. The whole network is held together by the vision of creating the Salafi state. A fuzzy, idea-based network really requires an idea-based solution. The war of ideas is very important and this is one we haven?t really started to engage yet.

Read the entire article.