In 1965, Ace Books exploited a loophole in U.S. copyright law to publish the first-ever paperback edition of the Lord of the Rings trilogy without the J. R. R. Tolkiens permission. At the time, American law required foreign-printed books to be manufactured domestically to maintain full copyright protection; because the original U.S. hardcovers used pages printed in the UK, Ace's editor argued the work had fallen into the public domain. Despite Tolkien's initial distaste for the "degenerate" paperback format, this unauthorized release sparked a fierce "War over Middle-earth." Tolkien personally mobilized his growing American fanbase to boycott the "pirated" editions, famously informing readers that Ace was "not so much a publisher as a pirate."