Mr. Berman's book has already made some noise. Writing in Slate, Ron Rosenbaum compared its stinging ambience, nostalgic to some, to one of "those old Partisan Review smackdowns," in which Dwight Macdonald or Mary McCarthy cracked some unsuspecting frenemy over the head with a bookcase and a tinkling highball glass. And for sure, everything about "The Flight of the Intellectuals" feels old school, from Mr. Berman's tone (controlled, almost tantric, high dudgeon) to the spectacle of one respected man of the left pummeling another while the blood flows freely, and no one calls the police.

Those Partisan Review fights got serious, and so does this book. Mr. Berman accuses Mr. Buruma, in his Times Magazine profile, of not scrutinizing Mr. Ramadan's family, associations or writings closely enough, of presenting him in a respectful light. Presenting him, that is, as the kind of moderate and charismatic Islamic thinker in whom the West might find a useful intermediary.

Mr. Berman's book, portions of which first appeared in The New Republic, is a patient overturning of the rocks that, he argues, Mr. Buruma failed to look under. He writes about historical figures Mr. Ramadan professes to admire and notes the tiny degrees of separation that link them to Hitler and the Nazis during World War II. He points out Mr. Ramadan's ambiguous comments about things like 9/11, the stoning of women in Muslim countries and violence against Jews. Mr. Berman detects a kind of seventh-century barbarism lurking behind Mr. Ramadan's genial smile.

Mr. Berman branches out in his book's final third to condemn liberal intellectuals (nearly all of them but especially Mr. Buruma and the British historian Timothy Garton Ash) and their house organs, including The New York Review of Books, on another, related, account. He writes that while they have admired Mr. Ramadan, they have been inexplicably critical of Ayaan Hirsi Ali, the Somali-born Dutch intellectual who has become a major critic of Islam and, as a consequence, will probably have a large security detail for the rest of her life. Ms. Hirsi Ali's critics, who include Mr. Buruma and Mr. Garton Ash, find her personality "strident" and humorless, he writes, and feel she isn't as important as she might be because having renounced Islam, she no longer speaks to or is in touch with the Muslim hive mind.

About these criticisms of Ms. Hirsi Ali, Mr. Berman is incredulous. "A more classic example of a persecuted dissident intellectual does not exist," he notes about her. And yet, he writes, she is treated differently from Salman Rushdie, another writer who was subjected to death threats. "How times have changed!" he declaims. "The Rushdies of today find themselves under criticism, contrasted unfavorably in the very best of magazines with Tariq Ramadan," who had ties to an organization that was known to be anti-Rushdie. "Here is a reactionary turn in the intellectual world — led by people who, until just yesterday, I myself had always regarded as the best of the best."

He is withering about why this might be. Quoting another writer, he calls this "the racism of the anti-racists." As self-hating Westerners, he suggests, Mr. Buruma and Mr. Garton Ash can be seen "groveling to Ramadan, who berates the West" while attacking the Somali dissident who embraces its values.

Fear is at work too, he says. About the chill in the intellectual climate, Mr. Berman writes: "Two developments account for it — two large new realities that, condensing overhead, have altered the intellectual atmosphere down below, almost without being noticed. The first of those developments is the spectacular and intimidating growth of the Islamist movement since the time of the Rushdie fatwa. The second development is terrorism."

Mr. Berman, whose previous books include "A Tale of Two Utopias," about the 1960s, and "Terror and Liberalism," is skilled at the art of polemic: he builds his case slowly, citing the recent work of numerous scholars. There is especially fascinating material here about Hitler's plan, aided by some Islamists, to extend the Final Solution to the Middle East.

Mr. Berman can be bleakly funny. He criticizes Mr. Garton Ash for pointing out in The New York Review of Books that Ms. Hirsi Ali had been awarded the "Hero of the Month" prize from Glamour magazine, as if this were proof that she couldn't be taken seriously. Mr. Berman responds, in one of this book's more memorable utterances: "I can't help observing that here may be proof, instead, that Glamour magazine nowadays offers a more reliable guide to liberal principles than The New York Review of Books."