Citing backlash, ISBNdb removed its webpages about training AI, denied ever buying, scanning, or selling a book for AI training, and said the site was a "test of market interest."

Its pitch is simple: older books offer cleaner data. "The world's best AI training data is sitting on a shelf," the company says on its website. "Books...

Before AI can learn from old books, someone has to scan them. For millions of physical copies, that has meant cutting off the spine.