Agatha Christie is widely regarded as the most successful fiction author of all time, with over two billion copies of her detective novels sold worldwide but I would suggest Karl Marx was the most successful fiction author of all time.
Overall, Marx’ complete collected works fill fifty volumes (including articles, letters, and drafts), he authored roughly fifteen primary independent works or major book projects, many of which were left unfinished or published after he became a good communist.
And, we know the communist country printing presses produced hundreds of millions of copies of these turgid and long-winded novels.
So I would contend Marx is the leading fiction writer of all time.
