Tolkien and Houghton Mifflin were aware of the potential copyright problems that loomed, and by early 1965, they were taking steps to publish a new version which they could copyright in the U.S. In April of 1965, they received word that Ace was about to publish their own version of the trilogy, one that would be priced competitively. At this point, Tolkien had already moved on to other projects, and was reluctant to return to editing The Lord of the Rings, given its length and complexity. In the meantime, Ace released their version of The Fellowship of the Ring in May, with The Two Towers and Return of the King following July of 1965. In August, Tolkien delivered his new revisions to Ballantine Books, the publisher which would release the official American editions. Interestingly, Humphrey Carter, in Tolkien’s official biography, noted that while Tolkien was displeased with the Ace editions, they at least sported covers that resembled their stories; by contrast, Tolkien was distressed at the cover art for the Ballantine editions, to which he noted: “What has it got to do with the story? Where is this place? Why emus? And what is the thing in the foreground with pink bulbs?”