"Dan Brown writes sentences like 'The famous man looked at the red cup.'" —Stewart Lee
Dan Brown is a very successful writer of action/suspense novels, including The Da Vinci Code, Angels and Demons, and The Lost Symbol. His plot-lines usually involve fact, pseudoscience and pseudohistory mixed in such a way as to leave less aware readers totally confused. How far Mr Brown himself believes these ideas is a matter for conjecture.
In a 2009 interview, Dan Brown described himself as a skeptic and that he "gravitated away from religion."
 The Da Vinci Code
The Da Vinci Code tells the story of a conspiracy to hide the fact that Jesus was married to Mary Magdalene and had children. The novel also depicts the Knights Templar as Gnostics who were in on the secret. The book uses footnotes to backup its outlandish claims even though they are bullshit.
This book was also made into a bad movie with Tom Hanks.
 A mercifully short summary
Jesus and Mary Magdalene had children, went to France, founded the Merovingian bloodline, the bloodline being considered the true Holy Grail. This conflicts with accepted Christian doctrine, and the equally realistic Indiana Jones and The Last Crusade. Many centuries of secrecy followed. Along came the Priory of Sion and the Knights Templar, tasked with preserving the secret of the Grail. The Catholic Church, specifically Opus Dei, were eager to preserve Christ's lifestyle as a confirmed bachelor, and thus the fun begins.
Some of those who should have been keeping the secret decided to leave odd little clues around, Leonardo Da Vinci's The Last Supper being an example of this. A curator at the Louvre was murdered by a sinister albino monk, but not before he managed to leave clues written in his own blood. From this follows lots of running around the world, the sinister albino monk in hot pursuit, and finally a reading of Leonardo's secret message indicating that the Grail (Magdalene's remains) is buried beneath the pyramid in the Louvre. You'll thank me for saving you from having to watch the movie. If you want crazy pseudo-history then watch National Treasure. At least in that case the author hasn't tried to sell it as being in any way factual.
The book was generally derided by critics and the literate, but this didn't prevent it from becoming the second-best selling book of 2004. Conspiracy theories sell - as do books with lots of implausible plot twists, plenty of action and exotic locations all wrapped up in short and easy sentences. The Da Vinci Code became the book that simply could not be avoided, and in the same way that born again Christians feel the need to share their profound discovery with everyone, innocent dinner party participants could scarcely escape having Brown's "revelations" shared with them.
Sony Pictures produced a movie based on the book. The movie became the fifth highest grossing film of 2006, behind equally realistic Pirates of the Caribbean: Dead Man's Chest, Night at the Museum, Cars, and X-Men: The Last Stand 
The Catholic Church and Opus Dei were not overly impressed by Brown's book or the movie adaptation. The church urged a boycott, while Opus Dei asked that a disclaimer be added to the movie. As is often the case with religiously motivated outrage, this probably just encouraged people to see what all the fuss was about.
 Sued for copyright infringement
The background of The Da Vinci Code is borrowed from a book named Holy Blood, Holy Grail. This book was sold as a non-fictional historical account of Christ's babymaking with Magdalene and the subsequent cover-ups instituted by the Catholic Church. The authors sued Brown for copyright infringement, but the case was decided against them. The Judge ruled that history and theories are not protected by copyright law, regardless of their accuracy. The moral of the story here is to avoid presenting confabulation as fact if you want to sue people who write a novels based on your junk. Another moral is: if a novelist has a hit using your work as a plot device, reissue your book with a sticker saying "the truth behind the novel" instead of getting on your high horse.
 Angels and Demons
The Da Vinci Code is more or less a sequel to Angels and Demons. In this book, the Illuminati have apparently placed antimatter (in a miraculous annihilation-proof container) somewhere in the Vatican, although it all turns out to be a stupid prank in the end. Brown seems to have decided that scientific absurdities would be a good complement to conspiracy theories.
This was also made into a movie starring Tom Hanks. It was marginally better than The Da Vinci Code movie, because it didn't take itself too seriously and knew that the whole thing was a bit of a farce. In this respect, it was not like the book. Also, the movie changed the story so that Angels and Demons was a sequel to The Da Vinci Code, because apparently only George Lucas and Peter Jackson are allowed to make prequels.
 Plot Summary
Brown's character searches Rome's most famous tourist destinations for clues to the location of a jar of antimatter stolen from CERN that will blow up the Vatican in 24 hours when it annihilates.
 Scientific Inaccuracy
The book features the collection of extremely large amounts of antimatter, portable containers that can hold it without annihilating, and the main character's survival of a fall from a helicopter by using a nine square-foot tarp as a parachute. However, the most absurd suggestion of the book by far is that two people could have a fight in the fountain in the Piazza Navona without anyone noticing.
 The Lost Symbol
While it contains the usual level of pseudohistory which readers have come to expect, in this novel Mr. Brown goes somewhat off the deep end with the pseudoscience - especially with its enthusiastic promotion of Noetic science and the Washington, D.C. street design conspiracy theory.
 Plot summary
Dan Brown's hero has to race around a capital city solving strange enigmas while showing how clever he is to a pretty girl - so it's really the same as the last two. The only change in this one is that the Masons are really really Good Guys, and the CIA is responsible for security in Washington.
 Anthropological usefulness
If a conspiracy theory is even alluded to in this book, then it has conclusively jumped the shark.
- ↑ http://www.youtube.com/watch?v=-yUDh_IErT4
- ↑ http://www.telegraph.co.uk/culture/books/booknews/6232148/The-Lost-Symbol-and-The-Da-Vinci-Code-author-Dan-Brown-50-factual-errors.html
- ↑ http://www.parade.com/news/2009/09/13-dan-brown-life-after-da-vinci-code.html
- ↑ The New York Times review of The Da Vinci Code.
- ↑ Language Log
- ↑ Box Office Mojo's details on the movie adaptation
- ↑ Judge rules on it's okay to borrow ideas from faux historical works