Conversation so far:
how long was the da vinci code on the bestseller list
The Da Vinci Code was on the best seller list for more than two years.
When was the book of Da Vinci Code published
The Da Vinci Code became one of the first notable international literary events of the twenty-first century as soon as it was published in early 2003.
Who is the central character in Da Vinci Code
The central character is Robert Langdon, a Harvard professor of symbology who first appeared in Brown's Angels and Demons, a 2000 novel with mediocre sales.

Question: What is the novel about
Self-contained rewrite: What is the novel of Da Vince Code about