It has been suggested by the, uh, Big Mind that the PhD recommend a few books (!!!) that might be of interest to those following #aghosTStory.
The Name of The Rose comes to mind. (Umberto Eco, 1983)
In a detective story set in a 14th Century monastery - if that isn't creepy enough - we are led through murders, sorcery, politics, religious wars, and secret tunnels, all set forth in a style both erudite and humorous. [ sidebar: the movie starred Sean Connery ]
Old tome :: must read.
A Rose is not simply A Rose in this labyrinth of symbols, arcana and numerology.