The Lord of the Rings - Ace Editions
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Ace released these paperbacks believing that the books were out of copyright due to how Houghton Mifflin had been importing hardcover editions from the United Kingdom. Eventually Ace capitulated their position and paid royalties to J. R. R. Tolkien, and only the "official" paperbacks released by Ballantine were left in the market. There are a lot more copies of the Ace editions in circulation than the first printings of the Ballantine editions, but because of the notoriety of these books they command a higher price in the current resale market.