Jansen, a professor at Leiden University in Holland, is one of the most astute and daring writers on fundamentalist Islam. His title points to the rather pedestrian fact that fundamentalist Islam “is both fully politics and fully religion,” but the book offers the author’s deep understanding of this phenomenon, which he characterizes as an “unusual combination of logic, religion, politics and violence.”

Jansen shows how fundamentalist Islam is “religion narrowed down to an ideology” but is still a religion, albeit one concerned with earthly power. He establishes that it is not a protest against being poor but an invariably successful form of propaganda “because the public to whom it is addressed love to hear it.” The two chapters on fundamentalist attitudes toward Jews and women are among the most incisive anywhere. But the most interesting chapter may be “the failure of the liberal alternative,” in which Jansen establishes that the anti-fundamentalists have “no weapons other than words” and so are steadily losing to the fundamentalists, who have large masses of followers.

Jansen’s book is not so much a systematic study as a series of musings by an original and provocative mind, primarily concentrating on Egypt. He reads the writers others only cite, such as Faraj Fuda and Shukri Mustafa. He chides not just fundamentalists, but also the ulema and fellow orientalists for absurdities and errors in logic. Islam, he says, obviously must be tolerated in an open society, “but does this extend tolerance to Islamic fundamentalism, too?” Yes, he replies, if it is a legitimate form of Islam; but not if it is a political ideology.