The New York Review of Books

In London eight men—all British nationals—are currently on trial for an alleged 2006 plot to destroy seven transatlantic aircraft in mid-air, using liquid explosives disguised as soft drinks. According to the prosecution they could have killed some 1,500 people, nearly half the number of those who died in the September 11 attacks. The airport security staff were to have their attentions distracted by “dirty” magazines in the would-be suicide bombers’ hand luggage—a neat example of jihad-by-pornography, fighting the infidel West with its own salacious habits.

In a video testament intended for posthumous transmission, one of the would-be martyrs berates the British people for their apathy toward their government’s policies in Iraq and Afghanistan:

This is revenge for the actions of the USA in the Muslim lands and their accomplices such as the British and the Jews…. Most of you [are] too busy…watching Home and Away and EastEnders [two popular TV soaps], complaining about the World Cup, drinking your alcohol, to even care anything…. I know because I’ve come from that.

What are the forces that drive young men such as these to commit mass murder? The question is addressed from different perspectives in all of the books under review.

A convincing analysis is offered by Marc Sageman, a forensic psychiatrist and consultant to the US government, in his Leaderless Jihad: Terror Networks in the Twenty-first Century. After examining some five hundred individual cases using “open source” data from court proceedings, media accounts, academic writings, and selected Internet materials, Sageman sets his gaze on what he calls the “middle range.” These are the social networks and intellectual milieus through which defendants in terrorist trials are recorded as operating. Contrary to widespread assumptions, he finds that they are not to be distinguished from their nonterrorist peers by extremes of hatred for the West:

It is actually difficult to convince people to sacrifice themselves just because they hate their target…. On the contrary, it appears that it is much more common to sacrifice oneself for a positive reason such as love, reputation, or glory.

A common theme, however, was geographical displacement. A very high proportion of his sample—84 percent—belonged to the Muslim diasporas, with a majority joining global Islamist terrorist movements in a country where they did not grow up. The Hamburg cell that provided the leadership for September 11 was typical of his wider sample: they were Middle Eastern students in Germany, who traveled to Afghanistan to join the fight against America.

Sageman pays close attention to family networks, with about one fifth of his sample having close family ties with other global Islamic activists. His point is strongly reinforced by Bilveer Singh in The Talibanization of Southeast Asia, his study of jihadist groups in Southeast Asia. Singh sees kinship as being a vital element in the makeup of al-Jamaat al-Islamiyah—the organization responsible for the Bali nightclub bombings in October 2002. The people who form terror groups have to know and trust …