The film Angels & Demonsis loosely based on the Novel written by Dan Brown which is titled the same. The Novel itself was published prior to The Da Vinci Code and chronologically takes place prior to the events in The Da Vinci Code. The movie Angels & Demonsis set up as a sequel to the movie The Da Vinci Code. Many critics and movie goers alike agree that the movie is the worst book adaptation ever released. Due to time constraints it is virtually impossible to include every detail of a book in a movie. However, characters and key plot issues were changed in the movie that ruined the story line for the fans of the book.

The plot is that an ancient organization known as the Illuminati has re-surfaced to take revenge against the Catholic Church. Four Catholic Priests are kidnapped on the eve of Conclave when a new pope is to be selected. The Illuminati stole a tube of anti-matter from the research facility CERN in Switzerland and they have hidden it somewhere inside Vatican City. Robert Langdon, a world renowned Harvard symbologist is brought in by CERN to decode a mysterious symbol burned in the chest of a CERN scientist.

Langdon embarks on a frantic search of old catacombs, sealed crypts, empty cathedrals, and into the greatly restricted vault of Vatican City itself to search for the trail of enlightenment which would lead to the location of the secret Illuminati meeting place that had been hidden for centuries. This is the epic battle between science and religion.

The film was directed by Ron Howard who also did The Da Vinci Code movie.  As Director, Ron Howard liked the idea of releasing Angels & Demonsas a sequel and not a prequel as it was originally written.  He said he did this because he felt more people had read Angels & Demons after the read The Da Vinci Codeand he liked the idea of portraying Robert Langdon as already having a past with the Catholic Church. 

Shooting of the film began in June of 2008 on location in Rome.  Three weeks of exterior shooting was scheduled in anticipation of a strike of the Screen Actors Guild around June 30th.  The film began under a fake working title called "Obelisk".  The rest of the film was shot at Sony Motion Picture Studios.  Roman Catholic Church officials did not like The Da Vinci Codeand therefore forbade any filming in actual churches.  Caserta Palace was used as a substitute for The Vatican and Biblioteca Angelica was used for the Vatican Library.

Many characters that were in the book were changed for the film adaptation.  These include:

• Vittoria Vetra's father, Leonardo Vetra was replaced by is replaced with Silvano, a research partner.
• In the novel the camerlengo is Italian and named Carlo Ventresca, in the film he is Northern Irish and named Patrick McKenna.
• In the book the Swiss Guard commander was Olivetti and in the movie the head of the Swiss Guard is Richter and Olivetti is in charge of the Vatican Police.
• Gunther Glick and Chinita Macri appeared in the book, but do not appear in the film at all.
• Maximilian Kohler, director of CERN does not appear in the movie at all.  His role is divided between a Vatican Police Representative and Commander Richter.

There are also several plot changes such as:

• In the book the deceased Pope was already buried and Conclave was about to begin, in the movie the funeral of the Pope was added.
• In the book, Langdon is summoned to Switzerland to CERN, in the movie he is visited by Vatican Police and taken to the Vatican.
• In the book only Vittoria and her father worked on the anti-matter and her father was murdered.  In the movie she appears to work on the anti-matter with a research assistant named Silvano and a team of scientists.
• In the novel only Langdon, Olivetti, and Vittoria confront the assassin at the Third Alter of Science, Olivetti is killed and Vittoria is kidnapped.  Langdon hides under a tomb and is found by police after the alarm on his watch goes off.  In the movie the assassin is surprised by the police and Langdon and Olivetti.  Vittoria is back at the Vatican and is not kidnapped.  Langdon hides under a grate and is found by police when they hear him hitting it with a rock.
• In the novel the last brand is the Illuminati Diamond which consists of an ambigram of the words Earth, Fire, Air, and Water.  In the film it is two keys crossed together which according to Langdon it symbolizes St. Peter's upside down Crucifixion. 
• in the book all four of the Preferiti are killed, in the movie the last one is saved by Robert Langdon and later becomes pope.
• The book is a prequel to The Da Vinci Codeand in the movie it is a sequel.  This is further evident by the subtle placement of a picture of Sophie Neveu on Robert Langdons bookshelf in the movie.

Over all the movie did not live up to it's built up hype.  It did little justice to the book, which was superbly written.  The plot and character changes made the movie somewhat hard to follow for those who had read the book.  Tom Hanks delivered a great performance as usual, but it wasn't enough to make the movie great.