What is the Best Selling Trilogy and Series of All Time?
Scholastic reports that the seven-book Harry Potter series has sold more than 600 million copies worldwide, making it the best-selling book series of all time. It has also been published in about 85 languages.
If you mean specifically a three-book trilogy, the answer is more complicated. The Lord of the Rings is generally cited at 150+ million copies worldwide. Although we commonly call it a trilogy because it was published in three volumes—The Fellowship of the Ring, The Two Towers, and The Return of the King—Tolkien conceived it as a single novel divided into six books.
So the useful distinction is:
Best-selling series: Harry Potter — 600+ millionMost famous/best-selling three-volume work: The Lord of the Rings — 150+ million
A series can be extraordinarily powerful commercially because each successful book creates a built-in audience for the next.
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