Likely you have been reading about the Hachette v. Internet Archive litigation. This is an article that you might want to add to your reference list on the topic. This article by Maria Bustillos starts with an analogy:
Buying a book should be no different from buying an apple. When you buy an apple, the farmer can’t show up in your kitchen later and decide your time is up, and you’ve got to pay for it again. It’s yours forever—to eat, or paint in a still life, or cut up for a kid’s snack. And thanks to the first sale doctrine of copyright law, codified by Congress in 1909, the books on your shelves are yours forever, too, in exactly the same way your apple is; you’re free to read them (or not), loan them to friends, or sell them to a used bookshop, without restriction. Copyright law balances the public good—our collective right to access information—with the rights it grants to authors and inventors.
Are you intrigued? You can read the entire article on The Nation website.