The Professor’s ‘Pendulum’ : Books: In his second novel, Umberto Eco focuses on man’s affinity for grand schemes built on dubious premises.

It was a glorious Indian summer day in Manhattan, the kind that Umberto Eco ordinarily might spend roaming the city streets and drinking in the sights and sounds.

But these are not ordinary times for the portly, bearded university professor-turned-novelist, who created a literary sensation almost a decade ago with the publication of his first fictional work, “The Name of the Rose.”

His long-awaited second novel, “Foucault’s Pendulum,” has just been released in an English-language version by his American publishers, Harcourt Brace Jovanovich, and his schedule overflows with the usual rounds of interviews, book signings, lectures, readings and receptions to promote the book.

“My only pleasure is to obey my publicist,” he said with a sigh during an interview in the sun-filled tearoom of the elegant Fifth Avenue hotel where he was staying. “It is a pity, because I am a compulsive walker.”

Still, the amiable expression on his face seemed to say, that it is a small sacrifice for the adulation he and his new novel are receiving.

In Italy, where the book came out last year, it sold more than 600,000 copies in the first three months of release and launched a new wave of “Ecomania.” At one point, it was outselling its closest rival on the Top 10 list by about 100 to 1.

In this country, in the space of three short weeks, it has already climbed to the top ranking in the Washington area and holds the No. 3 spots on the Los Angeles Times and New York Times best-seller lists. His book signings have been mobbed by eager fans, and his readings, lectures and debates have played to packed houses. In addition, his American publishers are printing 25,000 more copies of the book to augment the initial run of 250,000 copies.

Along with its commercial success, the book has been greeted by overwhelming critical acclaim.

No one, of course, is more pleased at all this than the 57-year-old Eco, who, until the publication of “The Name of the Rose” in 1980, was little known outside of academic circles in his chosen field of semiotics, the study of symbols and signs.

“Every author has two dreams,” said Eco, who speaks fluent English with a lilting Italian accent. “One is to sell a lot of copies. The other is to have written such an important book that it is difficult to read. But to have both. . . .”

There is no denying that his latest book is difficult to read--in many ways, perhaps even more so than “The Name of the Rose.”

For starters, it is 641 pages long--almost 1 1/3 times as long as “The Name of the Rose.” What is more, it has a far more convoluted structure and ranges in subject matter over what at times seems like the whole of Western culture, from Jewish cabala, the medieval Knights Templars, Shakespeare and Celtic legend to Karl Marx, Afro-Brazilian voodoo, computer theory and Mickey Mouse.

But in much the same way that he wrapped the medieval theological disputes and disquisitions in “The Name of the Rose” around a good old-fashioned murder mystery to hold the reader’s interest, so he has plotted “Foucault’s Pendulum” around a compelling adventure mystery.

What is more, his presentation of the often arcane and abstruse history in the book is seldom dull or unreadable.

For example, in describing the rise of the Knights Templars, a militant religious order established among the Crusaders in the early 12th Century, Casaubon, the narrator and one of the chief characters of the book, says: “Remember, the new kingdom of Jerusalem was sort of the California of the day, the place you went to make your fortune. Prospects at home were not great, and some of the knights may have been on the run for one reason or another. I think of it as a kind of Foreign Legion.”

Eco says the fascination his books hold, despite the difficulties they pose for readers, is easily explained.

“There are many books that are adventures, in which someone is going through a forest, in which a lot of strange trees with exotic names are mentioned,” he said. “You may not know the names or the shapes of the trees. But you continue reading because you participate in a sort of an agreement with the author. Now suppose that, instead of using nature, the author uses culture, as I do. The effect is the same.”

“Foucault’s Pendulum,” eight years in the writing, is the story of three editors at an obscure publishing house in Milan who get caught up in a hoax of their own making involving a supposed Knights Templars plan to tap a mystic source of power greater than any other known on Earth.

In the end, they are hoist by their own petard--in the case of one character, almost literally so.

Eco says the book is a cautionary tale against a problem that has plagued mankind for centuries: the all-too-human passion for concocting some grand scheme--usually conspiratorial in nature--then, finding hidden meanings in the least little things to back it up.

In many cases, Eco says, such intellectual machinations are relatively harmless--like the 19th-Century literary tracts that sought to prove, through their eccentric interpretations of “The Divine Comedy,” that Dante was a Rosicrucian, even though he lived hundreds of years before the mystic order’s founding.

At other times, however, the results of this “plotomania,” as Eco calls it, can have disastrous consequences.

He gives as an example the so-called Protocols of the Elders of Zion, a fabrication of anti-Semitic czarist Russians alleging a Jewish plot for world conquest that the Nazis used to help justify their systematic extermination of European Jews during World War II.

“The Protocols are a classic example of a concoction born of pure paranoia,” Eco said. “They are a pure comic text, full of contradictions. You can’t take them seriously.” But this, he added, does not stop anti-Semites from continuing to accept them as Gospel truth--or some close approximation of it.

“Take the attitude of one Nesta Webster, a reactionary, anti-Semitic Englishwoman,” he said. “She was mad but not stupid. She recognizes that the Protocols cannot be authentic. But, she says, that doesn’t matter because they say exactly what the Jews think.

“It’s fundamentally fascist, this way of looking at things and continuously finding connections. Why are you wearing a red tie?” he asked, his gravelly voice taking a suddenly peremptory tone as he noted an interviewer’s bright crimson knitted tie.

“Were you a premature anti-fascist of the times of McCarthy? Are you a secret Communist? . . . You see what I mean? You can do anything once you start down that path of reasoning.”

In “Foucault’s Pendulum,” the three plotomaniac editors are started down the path when approached by Col. Ardenti, a former Foreign Legionnaire who sports an Adolphe Menjou mustache. He starts the ball rolling by telling them he has discovered a centuries-old coded message involving the supposed Knights Templars plan to harness the mystic power source.

Shortly afterward, the colonel disappears and is presumed to have been murdered. From then on, the story spins out in an ever-growing web of intrigue, deception and intellectual excess that eventually snares the editors.

Although Eco says that the moral of the story is contained in every chapter in one way or another, it never seems more directly and eloquently stated than when Casaubon, the story’s narrator, says: “I have come to believe that the whole world is an enigma, a harmless enigma that is made terrible by our own mad attempt to interpret it as though it had an underlying truth.”

Oddly enough, Eco did not know whether he had another novel in him after he had completed “The Name of the Rose,” which has gone on to sell more than 9 million copies in 24 languages in hard- and soft-cover editions.

“I have to start writing from some personal obsession,” he said.

The obsession, in the case of “Foucault’s Pendulum,” came in the form of two images with which he had long been fascinated.

One was the pendulum designed by the 19th-Century French physicist Jean Bernard-Leon Foucault to demonstrate the Earth’s rotation. Eco first saw one of the devices 25 to 30 years ago hanging in a Paris museum, the Conservatoire des Arts et Metiers.

The other image was of a scene out of his childhood in Italy during World War II, when he played the trumpet at a burial ceremony in a country village for some anti-fascist partisans.

“I started thinking about what could be in between those two images in a book,” Eco said. “One year later, I started finding out.”

How precisely he fitted everything between those two images is evident in the book. The opening chapter finds Casaubon gazing upon Foucault’s pendulum as he hides out in the Conservatoire des Arts et Metiers. The penultimate chapter is a haunting lyrical one based on Eco’s trumpet-playing experience.

“I love that cemetery story,” Eco said with a wistful look in his dark eyes. “I have told it a lot to my friends over the years. Also, to many women to seduce them.”

Although he has had several offers, Eco said that he has no intentions of allowing the book to be made into a movie because of what he describes as the risk to the novelist.

“When the book is like ‘Death in Venice’ and the movie arrives 40 years later, there is enough distance from the book so that people won’t make a comparison between the two,” he explained. “But when the movie arrives too early on the shoulders of the book, there will be too many people who read the book through the movie, and this betrays the book.”

Besides, he added with a smile, “I don’t think it’s possible to make a movie out of ‘Foucault’s Pendulum’--except to make a sort of Vincent Price movie.”

No doubt, too--although he prefers not to discuss it--his experience in seeing “The Name of the Rose” translated to film has soured him on having “Foucault’s Pendulum” turned into a movie.

Ironically, for a book written as a caution against making unwarranted connections, “Foucault’s Pendulum” has stimulated many a reader to try his own.

Eco said that he is often questioned about the possible significance of the fact that the last names of the three editors start with the initial letters B, C and D--Belbo, Casaubon and Diotallevi--and that they are furthered in their scheme by three characters whose names each begin with the letter A--Col. Ardenti, Signor Aglie and a computer dubbed Abulafia after a Jewish cabalist.

“And another person has noted that Jacopo Belbo drinks a lot and that his initials are the same as a popular whiskey, J & B,” Eco said, dismissing such speculation as nonsense with a wave of his hand. “Once you start, as I said, you never can stop.”

However, he does not deny that there may have been some unconscious intent of which he was and remains totally unaware.

“A friend of mine once asked me why I chose the name Amparo for the Brazilian woman Casaubon has an affair with,” he recalled. “‘He said it was pretty strange because it’s a Spanish name and not Brazilian--a fact I note in the novel. He asked me if I had known someone named Amparo.”

Eco told the friend that he had once had an affair with a Latin American woman who served as the model for his fictional creation. But she was not Brazilian and her name was not Amparo. Only later, however, did he recall that when he was writing the scenes between Casaubon and Amparo, he would think of his old Latin American flame and how she used to played “Guantanamera” for him on her guitar.

“And then I remembered in one of the lines of that song there is a reference to a mountain called Amparo,” he said. “So probably from my guts it came up in my writing. Did I have any conscious intent? No.”

Success as a novelist has not changed Eco much, although he finds celebrity consumes a lot of precious time that he would rather devote to writing and to his scholarly pursuits. He still teaches classes at the University of Bologna.

But there are compensations--like seeing his first book, “The Aesthetics of Aquinas,” which was based on his doctoral dissertation, printed recently in an English-language version by Harvard University Press.

“It is absolutely true that I am happier of those 2,000 copies of the Harvard University Press than the millions of ‘The Name of the Rose,’ ” he said. “It was the only one of my books that had never been translated because it was difficult. Even in Italy, the first edition was a small university press run of about 500 copies.”

Is there another novel in the works?

“It’s possible,” he said. “One reason I started the second was to separate myself from the first. Otherwise, you become a prisoner to the book. It’s possible that, at a certain point, if I feel too pressured by the ‘Pendulum,’ I will be obliged to start thinking about another story.”