Dan Brown (born June 22, 1964) is an American author of thriller fiction, best known for the 2003 bestselling novel, The Da Vinci Code and the 2000 bestselling novel, Angels & Demons. Brown is interested in cryptography, keys, and codes, which are a recurring theme in his stories. Currently his novels have been translated into more than 40 languages. Brown states on his website that his books are not anti-Christian, as he is a Christian himself, and says of his book The Da Vinci Code that it is simply "an entertaining story that promotes spiritual discussion and debate" and suggests that the book may be used "as a positive catalyst for introspection and exploration of our faith".

While in Los Angeles, Brown joined the National Academy of Songwriters, and participated in many of its events. It was there that he met Blythe Newlon, a woman 12 years his senior, who was the Academy's Director of Artist Development. Though not officially part of her job, she took on the seemingly unusual task of helping to promote Brown's projects; she wrote press releases, set up promotional events, and put him in contact with individuals who could be helpful to his career. She and Brown also developed a personal relationship, though this was not known to all of their associates until 1993, when Brown moved back to New Hampshire, and it was learned that Blythe would accompany him. They married in 1997, at Pea Porridge Pond, a location near North Conway, New Hampshire. In 1993, Brown released the self-titled CD Dan Brown, which included songs such as "976-Love" and "If You Believe in Love". In 1994, Brown released a CD entitled Angels & Demons. Its artwork was the same ambigram by artist John Langdon which he later used for the novel Angels & Demons. The liner notes also again credited his wife for her involvement, thanking her "for being my tireless cowriter, coproducer, second engineer, significant other, and therapist." The CD included songs such as "Here in These Fields" and the religious ballad "All I Believe."

In 1994, while on holiday in Tahiti, he read Sidney Sheldon's novel The Doomsday Conspiracy, and decided that he could do better. He started work on Digital Fortress, and also co-wrote a humour book with his wife, 187 Men to Avoid: A Guide for the Romantically Frustrated Woman, under the pseudonym "Danielle Brown" (one of the 187 items in the book was "Men who write self-help books for women"). The book's author profile reads, "Danielle Brown currently lives in New England: teaching school, writing books, and avoiding men." The copyright is attributed to Dan Brown. In 1996, Brown quit teaching to become a full-time writer. Digital Fortress was published in 1998. His wife, Blythe, did much of the book's promotion, writing press releases, booking Brown on talk shows, and setting up press interviews. A few months later, Brown and his wife released The Bald Book, another humor book. It was officially credited to his wife, though a representative of the publisher said that it was primarily written by Brown. Brown's fourth novel, The Da Vinci Code, became a runaway bestseller, going to the top of the New York Times Best Seller list during its first week of release in 2003. It is now credited with being one of the most popular books of all time, with 60.5 million copies sold worldwide as of 2006. Its success has helped push sales of Brown's earlier books. In 2004, all four of his novels were on the New York Times list in the same week, and in 2005, he made Time magazine's list of the 100 most influential people of the year. Forbes magazine placed Brown at #12 on their 2005 "Celebrity 100" list, and estimated his annual income at US.5 million. The Times estimated his income from 'Da Vinci Code' sales as 0 million. Characters in Brown's books are often named after real people in his life. Robert Langdon is named after John Langdon, the artist who created the ambigrams used for the Angels & Demons CD and novel. Camerlengo Carlo Ventresca is named after "On A Claire Day" cartoonist friend Carla Ventresca. In the Vatican Archives, Langdon recalls a wedding of two people named Dick and Connie, which are the names of his parents. Robert Langdon's editor Jonas Faukman, is named after Brown's real life editor Jason Kaufman. Brown also said that characters were based on a New Hampshire librarian, and a French teacher at Exeter, Andre Vernet.

In interviews, Brown has said that his wife is an art historian and painter. When they met, she was the Director of Artistic Development at the National Academy for Songwriters in Los Angeles. During the 2006 lawsuit over alleged copyright infringement in The Da Vinci Code, information was introduced at trial which showed that Blythe did indeed do a great deal of research for the book. In one article, she was described as "chief researcher".

In 2006, Brown's novel The Da Vinci Code was released as a film by Columbia Pictures, with director Ron Howard; the film starred Tom Hanks as Robert Langdon, Audrey Tautou as Sophie Neveu and Sir Ian McKellen as Sir Leigh Teabing. It was considered one of the most anticipated films of the year, and was used to launch the 2006 Cannes Film Festival, though it received overall poor reviews. It was later listed as one of the worst films of 2006, but also the second highest grossing film of the year, pulling in 0 million USD worldwide. The next film, Angels & Demons, is due for release on May 15, 2009, with Howard and Hanks returning.

Brown was listed as one of the executive producers of the film The Da Vinci Code, and also created additional codes for the film. One of his songs, "Phiano", which Brown wrote and performed, was listed as part of the film's soundtrack. In the film, Brown and his wife can be seen in the background of one of the early booksigning scenes.

In August 2005, Brown won a court case in New York against author Lewis Perdue over charges of plagiarism, on the basis of claimed similarity between The Da Vinci Code and his novels, The Da Vinci Legacy (1983) and Daughter of God (2000). Judge George Daniels said, in part: "A reasonable average lay observer would not conclude that The Da Vinci Code is substantially similar to Daughter of God".

On March 28, 2007, Brown's publisher, Random House, won an appeal copyright infringement case brought by authors Michael Baigent and Richard Leigh. The Court of Appeal of England and Wales rejected the efforts from two authors, who claimed that Brown stole their ideas for his novel The Da Vinci Code. Baigent and Leigh, who wrote Holy Blood, Holy Grail in 1982, argued that Brown stole significant elements from their book. Both are based on a theory that Jesus and Mary Magdalene married and had a child and that the bloodline continues to this day. Baigent and Leigh are liable for paying legal expenses of nearly million USD. Brown even alluded to the two authors' names in his book. Leigh Teabing, a lead character in both the novel and the film, anagrammatically derives his last name from Baigent's, while using Leigh's name verbatim. A contributing factor for the outcome of the case is that these authors presented their work as nonfiction. Fiction writers often draw upon nonfiction resources for content research.