It is satirical, being full of esoteric references to Kabbalah, alchemy, and conspiracy theories, to the point that critic and novelist Anthony Burgess suggested that it needed an index.

Casaubon's relationship with Amparo falls apart after attending an Umbanda rite, and he returns to Milan, where he is hired by Belbo's employer, Mr. Garamond,[d] as a researcher.

Belbo, Diotallevi, and Casaubon become submerged in occult manuscripts that draw flimsy connections between historical events, and soon have the idea to develop their own as a game.

Using Belbo's personal computer "Abulafia" and Ardenti's manuscript as a foundation, the three create what they call "The Plan" using a program that rearranges text at random.

The Plan eventually becomes an intricate web of conspiracy theories about the Templars and their goal to reshape the world using "telluric currents", which are focused at the Foucault pendulum.

In addition to numerous other historical organizations apparently involved in The Plan, the three invent a fictional secret society, the Tres (Templi Resurgentes Equites Synarchici, Latin for "the Risen again Synarchic Knights of the Temple").

While waiting in the villa, Casaubon finds an old manuscript by Belbo that relates a mystical experience he had when he was twelve, in which he perceived ultimate meaning beyond signs and semiotics.

[6][full citation needed][f] Most books written in this fiction genre seem to focus on the mysterious, and aim to provide their own version of the conspiracy theory.

Although the main plot does detail a conspiratorial "Plan", the book focuses on the development of the characters, and their slow transition from skeptical editors, mocking the Manutius manuscripts to credulous Diabolicals themselves.

This attitude of constant subconscious self-abasement fits in with the overall irony focused on in the book, considering that Belbo is eventually consumed by (re)creation of the Plan; one excerpt meant for the unattainable Lorenza reads, "I could not possess you, but I can blow up history."

His narratives abandon his strict realism and become increasingly inclined towards the supernatural as the novel progresses, despite periodic reality checks from his partner Lia.

Eco shows that if one stops discriminating between whether propositions are right or wrong, it is possible to link any fact or idea with any other, but that this creates a dangerous tendency towards conspiracy theories.

Eco reinforces this theme by quoting Karl Popper at the heading of chapter 118:[10] "The conspiracy theory of society ... comes from abandoning God and then asking: 'Who is in his place?

'".A wide variety of organizations are listed in Foucault's Pendulum, including the Assassins of Alamut, the Bavarian Illuminati, the Bogomils, the Candomblé, the Cathars, the fictional Cthulhu cult,[11] the Church of Jesus Christ of Latter-day Saints (which in the novel Mr. Garamond includes in his list of "occult" organizations to contact about book ideas), the Elders of Zion, the Freemasons, the Gnostics, Gurdjieffians, the Jesuits, the Knights Templar, Opus Dei, Ordo Templi Orientis, Panta Rei, and the Rosicrucians.

So Dan Brown is one of my creatures.Eco was indebted to Danilo Kiš's story "The Book of Kings and Fools" in The Encyclopedia of the Dead (1983) for the portrayal of Sergei Nilus.

Eco refers to his own visit to a Candomblé ceremony in Brazil in an article compiled in Faith in Fakes, reminiscent of the episode in the novel.