* Total copies sold of all books in the series?
* Total copies sold across all mediums (books, movies, merchandise)?
* Total revenue generated by the franchise?
Depending on the definition, the ranking will change.
However, "Lord of the Rings" is undoubtedly one of the best-selling and most successful franchises in history. Here's why:
* Book sales: "The Lord of the Rings" is one of the best-selling fiction books of all time, with estimated sales exceeding 150 million copies worldwide.
* Movie success: The "Lord of the Rings" film trilogy was a massive success, grossing over $2.9 billion worldwide.
* Merchandise and licensing: The franchise generates significant revenue from merchandise, including toys, games, clothing, and more.
While there might not be a definitive ranking due to the complexity of measuring "all-time sales," "Lord of the Rings" undeniably stands among the most commercially successful franchises ever.