Ambitious writers are often said to challenge their readers. That’s certainly true in the case of Umberto Eco and his latest novel, “The Prague Cemetery,” but not, perhaps, in quite the expected way. Let’s backtrack for a moment.

Eco’s first work of fiction, “The Name of the Rose” (1980), was set in an isolated medieval monastery, densely written and larded with passages in Latin, replete with theological speculation, almost entirely without female characters and concerned, in large part, with a lost manuscript by Aristotle. On the surface, none of this cries out international bestseller. Nonetheless, because “The Name of the Rose” was also a clever murder mystery, featured a Sherlock Holmes-like monk- detective and made readers feel intelligent just to have it on their shelves, whether they read it or not, the book made Eco’s name and fortune.

From there, the exuberant Italian — half savant, half bon vivant — went on to juggle a distinguished academic career focused on semiotics and cultural history with gigs as an occasional newspaper columnist and, every few years, the publication of a new novel. These last have tended to be what I call antiquar­ian romances: big books such as “Foucault’s Pendulum” and “The Island of the Day Before” that are packed with encyclopedic learning and ­often revolve around the occult, secret societies and conspiracy theories of history.

While “The Name of the Rose” was made attractive by the presence of William of Baskerville and by the naive young acolyte who narrates the story, Eco’s latest book, by contrast, features almost no one who isn’t contemptible or loathsome. In a loose sense, “The Prague Cemetery” can be viewed as an attempt to explore the mind of a fanatic from within, to explain the hate-filled prejudices and publications of the 19th century, and to proffer a plausible background for the compo­sition of the notorious anti- Semitic screed “The Protocols of the Elders of Zion.” In typical Eco fashion, the novel neatly links together most of the conspiracy mythologies of the era. Behind every war, every revolution, every financial triumph or disaster, the enlightened can always detect the hidden hand of the Jesuits, the Jews, the Freemasons, the Carbonari, the secret police, international anarchism or even Satan himself.

Setting aside the novel’s structural complexities, “The Prague Cemetery” basically traces the life and career of   the half-Italian, half-French ­Simone Simonini. Brought up by a grandfather who blamed the Jews for everything and by a father who saw the malign influence of the Society of Jesus everywhere, young Simonini grows up obsessed with the notion of conspiracy. Intellectually, he is molded by his reading of the era’s most lurid fiction, in particular, Alexandre Dumas’ “Joseph Balsamo,” about the occult charlatan Cagliostro, and Eugene Sue’s melodramatic serials featuring Jesuit masterminds, esoteric Masonic rituals and even the immortal Wandering Jew. Later, as a young man, Simonini discovers that he possesses a gift for imitating anyone’s handwriting, a taste for dressing up in clerical vestments, and a horror of female flesh and every form of sexuality. He exhibits as well a Parisian gastronome’s obsession with ­exquisite food and almost no moral sense whatsoever.

As the years roll by, our protagonist — one can hardly call him a hero — works as a spy and forger, eventually betrays everyone he knows and periodically catches up on the latest in bomb technology. He acts as a murderous double agent within Garibaldi’s army, presents an eyewitness account of the Paris Commune and its savagery, helps to falsely incriminate Capt. Alfred Dreyfus, eventually suffers what might be a case of split personality and even encounters the young Sigmund Freud. Oh, yes, and he also participates in a Black Mass and imagines the Final Solution. Eco certainly doesn’t stint on sensationalism.

But neither does he make up very much of this. Nearly all the characters, tracts, newspapers and events in the book are drawn from the historical rec­ord. It’s only Eco’s imagination that connects all these elements to a single shrewd and repulsive little worm. Here, in effect, is a conspiracy theory of conspiracy theories.

There’s certainly much to admire in “The Prague Cemetery.” Eco writes brilliantly about food, for instance. Simonini is an epicure who daydreams about recipes as other men do about women. The mere mention, he says of the specialties provided by the Cafe Anglais, “makes me feel that life is worth living.” Throughout his narrative, Eco also integrates dozens of contemporary steel engravings, almost transforming his book into a graphic novel. And it’s fun to hear the echoes of   J.K. Huysmans’s famous novel about rival Satanists, “La-Bas” (“Down There”), or to identify at least some of Simonini’s many allusions, such as — to take an easy one — his reference to “that consumptive Polish pianist kept by a degenerate woman who went about in trousers” (Chopin and George Sand).

Better still, every few pages Eco proffers a memorable, even aphoristic observation: “Someone said that women are just a substitute for the solitary vice, except that you need more imagination. . . . When a spy sells something entirely new, all he need do is recount something you could find in any secondhand book stall. . . . Any defamatory work ought to be readable in half an hour. . . . A mystic is a hysteric who has met her confessor before her doctor.” From his own early reading as well as his later experience, Simonini soon proclaims the “Universal Form of every possible conspiracy,” that is, our human proclivity to always find a culprit for life’s major setbacks and thus to confirm what we, subconsciously, already “know.”

Which is, of course, that none of us are ever truly responsible for our failures or misfortunes. We have, in fact, been held back and our dreams dashed by dark forces leagued against us. Nowadays, these might be the old-boy WASP, Ivy League network. Or those commie pinko-liberal sympathizers at work in our government. Or the Jews. It’s equally obvious that people of much less talent than we possess unjustly succeed because they are backed by Them, meaning the Mafia or the Church of Scientology or the all-powerful gay-lesbian lobby. Utter nonsense? Yes. Yet what makes all this tricky, of course, is that sometimes such suspicions aren’t wholly without substance, especially if one happens to be, for instance, black, Muslim, disabled or homosexual.

“The Prague Cemetery” is thus only partly historical. It addresses both humankind’s most nefarious bigotries and some unpleasant contemporary truths, notably that all too often our sense of “identity is now based on hatred . . . for those who are not the same.” One of the book’s anti-Semites is so completely deluded that he finally announces that “the idea that Christ was Jewish is a legend created by people who were Jews themselves. . . . Jesus was in fact of the Celtic race, like we French.” Who could doubt such a self-evident truth?

“The Prague Cemetery” is certainly engrossing and cautionary, but it mainly offers, to adopt Joseph Conrad’s biblical-sounding phrase, the appalling fascination of the abomination. Be aware, then, that Umberto Eco hasn’t produced anything close to what one might call a fun read or a light entertainment. “The Prague Cemetery” is, in fact, an all-out horror story.

Dirda reviews each Thursday in Style and conducts a book discussion for The Post at His latest book, “On Conan Doyle,” has just been published.


By Umberto Eco

Translated from the Italian by Richard Dixon

Houghton Mifflin Harcourt. 444 pp. $27