Before the incredible success of "The Da Vinci Code", Dan Brown wrote "Angels and Demons", the first book to feature Robert Langdon as the protagonist. Langdon is a Harvard professor and a symbologist. He studies and lectures on religious symbols and is an expert. His assistance is requested when there is a murder in a highly advanced scientific community. While Langdon questions why he is being asked to investigate a murder with no police involvement the reason is clear when the nature of the murder is revealed: burned into the chest of the victim is the symbol for the "Illuminati". The Illuminati is a secret organization which has its origins in the time of Galileo. The Illuminati were scientists persecuted by the Catholic Church and the organization became rabidly anti-Catholic.
While bringing the Illuminati into the story certainly adds complexity to "Angels and Demons", the stakes are raised once more when the murder leads to a theft of a small amount of man made anti-matter. This is significant because up until the murder victim, nobody had ever created anti-matter on earth and this is a highly volatile substance that even trace amounts can cause a great explosion. The amount of anti-matter stolen is enough to completely destroy city blocks and with the anti-Catholic nature of the Illuminati, the threat of the stolen anti-matter is directed at the Vatican. This is where Robert Langdon comes in. He has to follow a trail of symbols to stop a series of murders and the eventual destruction of the Vatican itself.
In the hands of a lesser writer, this could be an absurd story that fails to work on any level. Amazingly enough, Dan Brown has written a tight, fast paced story where the tension increases and increases as Langdon tries to unravel the symbols that provide a trail of clues to each potential murder victim and the danger touches the highest levels of the Vatican. "Angels and Demons" should not be as interesting as it turned out to be. This is a book that should be so heavy in detail that it weighs the narrative down, but it doesn't. "Angels and Demons" is a gripping story that pulled me in and did not let me go until near the end when Brown may have used one twist too many and the book finally did venture into the absurd. That one absurdity aside, the 9/10 of this book that worked was so good that I feel compelled to use that grand cliche about literature: "it was a real page turner". In this case the cliche is absolutely true. "Angels and Demons" is a "real page turner".
There are many similarities to "The Da Vinci Code". The theme and many of the events are remarkably similar, as are the villains and the ties to the Catholic Church, but where "The Da Vinci Code" was obsessed with the ideas of the conspiracy "Angels and Demons" tells a better story. "Angels and Demons" is the better book of the two (so far) Robert Langdon novels, but the ideas of "The Da Vinci Code" were far more interesting and controversial, which explains the difference in sales. If you haven't read "The Da Vinci Code" yet, start with this one.