In Eco's latest novel, The Prague Cemetery, his idée fixe mutates into a gothic fantasy embracing Jesuits, Freemasons and above all Jews, culminating in the most pernicious conspiracy theory of them all: the Protocols of the Elders of Zion. Eco claims that he has invented only one character, the protagonist Simone Simonini, whose fictitious diaries record how he forges the Protocols, frames Dreyfus and infects Europe with anti-Semitism. "But on reflection," he adds, "even Simone Simonini ... did in some sense exist. Indeed, to be frank, he is still with us." In other words, Eco deliberately confuses fact and fiction. Having immersed his readers in conspiracy theories against the Jews, he then leaves them wondering whether some of these vile slanders might, after all, be true.

The trouble with what his publisher calls "an inspired twisting of history and fiction" is that Eco is playing with fire. This time it is not a game. There is nothing esoteric about the Protocols, millions of copies of which circulate in the Muslim world. Anti-Semitism is on the march, not only in the Middle East but across the globe, including the West, fuelled by that multiplier of conspiracy theories, the internet. The leaders of Iran have made Holocaust denial state policy and signalled that they plan a second Holocaust, using nuclear technology supplied by, among others, Germany and Russia — the two worst persecutors of Jews in the recent past. Eco's frivolous treatment of Jew-hatred as a cloak-and-dagger mystery, to fund his collection of incunabula, while real Jews are targeted by terrorists from New York to Mumbai and from London to Buenos Aires has left many readers feeling queasy. 

The doubts sown by the book fall on fertile soil, for ours is a culture that long ago lost its bearings, thanks to the prestige of postmodernists such as Umberto Eco. He stands for the intellectuals of the 21st century who, like those of the last century, commit trahison des clercs by flirting with anti-Semitism when their duty is to take a clear stand against it.