* The Book of the Heretics
* The Academy
* The Scorpio
* The League
* The Rising
Non-fiction:
* The History of the Vatican
* The History of the Roman Catholic Church
* The History of the Inquisition
* The History of the Medici
* The History of Christianity
Short stories:
* "The Last Sacrament"
* "The Heretic"
* "The Inquisitor"
* "The Pope"
* "The Cardinal"