The Lord of the Rings — LotR — is an epic fantasy novel written by English author J. R. R. Tolkien.
The story began as a sequel to Tolkien's 1937 fantasy novel The Hobbit, but eventually developed into a much larger work. Written in stages between 1937 and 1949, The Lord of the Rings is the second best-selling novel ever written, with over 150 million copies sold.
While its initial impact on fandom was small — fandom in the 1950s was focused on SF and what fantasy it was interested in was either weird fantasy or heroic fantasy — by the early 60s it had developed a loyal following which blossomed into Tolkien fandom in the late 60s. On the darker side, it spawned the legions of Tolkien imitators which still plague the field today.
One of the more colorful events in the book's history happened in the early 60s when Houghton-Mifflin, the book's US hardcover publisher, turned down requests from paperback publishers to do a paperback edition. LotR had been selling steadily, if unspectacularly, for years and many thought that H-M didn't think that a paperback edition would sell — in those days, fantasy hardly had a market. It turned out, however, that due to an error that H-M made, the copyright on LotR in the US had lapsed and H-M didn't actually own any rights.
Someone at Ace Books — either Don Wollheim or A. A. Wyn — noticed this and decided to publish their own edition and, when it was published, The Fellowship of the Ring did very well, well enough that they decide to rush out the second and third volumes. (They were in such a rush that Jack Gaughan, who had been contracted to do the cover illustrations didn't have time to read the book. He contacted John Jakes, a friend who had been urging him to read it, and got enough of a description of what was happening to do credible cover illos.)
When fandom heard about this — and H-M made sure it got wide publicity, since they had gotten Tolkien to make minor revisions to the book so that a new copyright could be obtained int he US on the revised copy — there was an uproar and a boycott of the Ace edition. (Ace dropped their edition — it is unknown if the fannish boycott was a factor — and a H-M paperback edition became the standard US edition. Later, when Wollheim was asked if it wouldn' have been simpler just to pay Tolkien a royalty, he said that A. A. Wyn (the owner) would never agree to pay a royalty that he wasn't obligated to pay.)