Take it as I lost my big ass book
Still "you are forbidden to talk" rule applies
then you're forbidden to talk about realism and art. The authors that I mentioned are masters at writing books based on realism.
To give some examples that even you may have heard of,
Robert Ludlum is the author of the Jason Born Trilogy.
Frederick Forsyth is the author of The Day of The Jackal, The Odessa File, The Fourth Protocol, The Dogs of War.
Jack Higgins is the author of The Eagle has Landed.
Clive Cussler is the author of Sahara & Raise the Titanic!
Jack Higgins is the author of The Firm, A Time to Kill, The Pelican Brief, The Client, The Runaway Jury
Tom Clancy is the author of The hunt for Red October, Patriotic Games, Clear and Present Danger, The Sum of All Fears
Yes, all those were made in to movies. All these authors have written more books that weren’t made in to movies.
Read at least some of them before you make outlandish claims like Dan Brown's books are based on facts and realism.