What is the author trying to say in Angels and Demons?

The novel Angel and Demons , by Dan
Brown, is a fictional thriller based on scientific, historical, and theological
constructs.

In the story, Harvard professor Robert Langdon
is invited to investigate the kidnapping of the four top candidates for the Papal
throne. In addition to this, information leaks joining the Catholic Church with the
ancient sect of the Illuminati, and additionally joining these two entities with an
antimatter project that aims to re-enact the creation of the
Universe.

All this boils down to a few powerful
points:

• The Vatican is a financial, scientific,
  historical, political, and psychological world power; it is not just a branch of heaven
  on Earth.


• The Vatican freely and legally is allowed to
  hold information that leads directly to the making or breaking of key people, programs,
  and systems in place across the world. Brown argues that, among this information, there
  is the existence of extracted antimatter, the possession of secret historical documents,
  and the hosting of societies that are the true movers of the fate of
  civilization.


• The Catholic Church is more of a keeper of
  treasures than a religious sect.


• The Vatican is made of
  a mob of priests, radicals, and some other interesting people, who act against each
  other and have the potential to turn the world around.
  

Hence, Brown explores all the possible
mysteries that are actually hidden in the vaults of the Vatican, making the reader
understand that hundreds of years of secrets, security, and extreme control must be
happening there for a reason. What exactly goes on behind close doors in the so-called
House of God?