In 1965, The Lord of the Rings came out in the U.S. in paperback form, courtesy of sci-fi publisher Ace Books—and it did so without the authorization of Tolkien himself. Ace editor Donald A. Wollheim claimed that the works weren’t copyrighted in the United States, leaving them unprotected and ripe for publication. Selling for 75 cents each, the Ace version of The Lord of the Rings was a success, leading Tolkien to return to his books to make enough revisions to qualify them for copyright protection in the U.S.

Tolkien called upon his fans to boycott the Ace versions in favor of the newly updated, and official, paperbacks from Ballantine Books—though they cost around 20 cents more. Ace later agreed to stop printing the books and pay Tolkien a royalty for every copy sold. The combined sales totals of the Ace and Ballantine versions of The Lord of the Rings reached 250,000 in just 10 months.