One way to become a Famous Intellectual in France is to take a nonsensical thesis and be the first to write a whole book advancing it. By this standard, Kepel excels, for he adopts the preposterous idea that militant Islam is in decline and manages to fill 376 pages of text with examples and arguments that credibly support this idea. His only fault is a certain lack of originality, given that one of his colleagues, Olivier Roy, beat him to the punch by publishing L'Echec de l'Islam politique  a full eight years earlier. Both scholars, it bears noting, are much lionized and deeply influential in France. (In contrast, the best that Americans have mustered was a thin article by an obscure academic.)
Kepel's take differs from Roy's in that Roy made much of a distinction between two nearly identical streams of militant Islam (which he dubbed Islamism and neofundamentalism), while Kepel instead finds a sociological premise for dismissing militant Islam. It was doing well in the 1980s, expanding its base, but fell apart in the 1990s due to an inability of the Islamists to keep intact the alliance they had cobbled together of the young urban poor and the devout middle class.
To the question, what about September 11, 2001, Kepel breezily replies that this was a "provocation" that only confirms the "waning" of militant Islam. He deems it nothing but "an attempt to reverse a process in decline, with a paroxysm of destructive violence."
In addition to a thesis that flies in the face of all reality, Kepel also makes a string of factual whoppers of the sort that – were he not a Famous French Intellectual – would probably doom his career. Here are a few howlers from the introduction alone: he sees the entire decade of the 1980s "overshadowed by a power struggle between the Saudi monarchy and Khomeini's Iran" (forgetting a small episode called the Iran-Iraq war); he falsely attributes to the U.S. government the goal of supplying aid to the Afghans during the 1980s to precipitate the collapse of the Soviet Union (the goal was far more limited and defensive); he believes that the umma is the unit ruled by the laws of Islam (this is the body of all Muslims; Dar al-Islam is what he meant to say); and he somehow fails to find any signs of active support in the Muslim world for al-Qa‘ida's long-term objectives—to which one can only ask, where was he hiding out during September and October of 2001?
 Jihad: Expansion et Déclin de l'Islamisme. Paris: Gallimard, 2000.
 Paris: Seuil, 1992. Reviewed in MEQ, Sept. 1995, p. 88.
 Ray Takeyh, "Islamism: R.I.P." The National Interest, Spring 2001.