Angels & Demons shares many stylistic literary elements with its sequels, such as conspiracies of secret societies, a single-day time frame, and the Catholic Church.

[1] Leonardo Vetra, one of CERN's top physicists who have discovered how to create antimatter, is murdered, his chest branded with an ambigram of the word "Illuminati", an ancient anti-religious organization thought extinct.

CERN director Maximilian Kohler calls Vetra's adopted daughter, Vittoria, and Harvard University Professor Robert Langdon, an expert on symbology and religious history, for help.

Believing that the four cardinals will be ritually murdered on the four altars of the "Path of Illumination", Langdon and Vittoria follow a series of clues left in various churches in and around Rome.

Langdon also fails to save the last cardinal, who is drowned in the Fontana dei Quattro Fiumi, and confronts the assassin in the Castel Sant' Angelo, the Church of Illumination.

Mortati is unanimously elected Pope by the Cardinals, and Langdon and Vittoria reunite at Hotel Bernini where they spend the night together.

[3] Aside from the explicit introduction, the book depicts various fictional experts explaining matters in science, technology, and history in which critics have pointed out inaccuracies.

[4] Angels & Demons Decoded, a documentary on the American cable television network, The History Channel, premiered on May 10, 2009, shortly before the release of the novel's film adaptation.

Zimmer adds that the office was abolished by Pope John Paul II in 1983, 17 years before the novel was published.