* Varying definitions of "best-selling": Do we consider copies sold across all languages and editions? Or just original language printings? Do we include digital sales and audiobook sales?
* Lack of reliable data: Accurate sales figures are often proprietary and not publicly available for all novels.
* Historical context: Comparing sales across different eras is difficult due to changes in publishing and literacy rates.
However, some novels consistently appear at the top of "best-selling" lists, including:
* "Don Quixote" by Miguel de Cervantes: This 17th-century novel is often cited as one of the most influential and widely read books of all time.
* "A Tale of Two Cities" by Charles Dickens: Another classic, this 19th-century novel is estimated to have sold over 200 million copies.
* "The Little Prince" by Antoine de Saint-Exupéry: This beloved children's book has sold over 200 million copies worldwide.
* "The Lord of the Rings" by J.R.R. Tolkien: This fantasy epic has sold over 150 million copies worldwide.
* "Harry Potter" series by J.K. Rowling: The Harry Potter series is one of the most popular book series of all time, with over 500 million copies sold worldwide.
* "And Then There Were None" by Agatha Christie: This mystery novel has sold over 100 million copies worldwide.
Ultimately, the "best-selling novel" is subjective and depends on how you define "best-selling." These are just a few examples of novels that have achieved remarkable sales figures and cultural impact.