The book that Stanley Kubrick's cancelled project would be based on.
Foucault's Pendulum is an unfinished Stanley Kubrick project. The film would have been based on Umberto Eco's novel of the same name - about three friends who become dangerously interested in conspiracy theories and decide to create one on their own (called "The Plan").
Cancellation[]
Eco would not allow Kubrick to make a film adaptation of Foucault's Pendulum due to two reasons. Firstly, Eco was unhappy with a film adaptation of an earlier book of his, named The Name of the Rose. The second reason was Kubrick's unwillingness to let Eco write the screenplay. When Kubrick later died in 1999, Eco regretted not letting Kubrick film an adaptation.