You don't copyright a book, you copyright what's written in it. Copyright for a novel doesn't decide who owns each printed book, it creates a monopoly over the entire market of books containing that novel. If you own the copyright to a novel, no one but you is allowed to compete in the market of books containing your novel.

Sure, they can compete in the larger overall market of all books in general, but they must avoid the segment of that market that you own a copyright to.