Editor’s note: This article is part of The Atlantic’s series on Books3. You can search the database for yourself here, and read about its origins here. This summer, I reported on a data set of more than 191,000 books that were used without permission to train generative-AI systems by Meta, Bloomberg, and others. “Books3,” as it’s called, was based on a collection of pirated ebooks that includes travel guides, self-published erotic fiction, novels by Stephen King and Margaret Atwood, and a lot more. It is now at the center of several lawsuits brought against Meta by writers who claim that its use amounts to copyright infringement. Books play a crucial role in the training of generative-AI systems. Their long, thematically consistent paragraphs provide information about how to construct long, thematically consistent paragraphs—something that’s essential to creating the illusion of intelligence. Consequently, tech companies use huge data sets of books, typically without permission, purchase, or licensing. (Lawyers for Meta argued in a recent court filing that neither outputs from the company’s generative AI nor the model …