GoKawiilWhat we know so far: A market built for libraries and booksellers is now feeding AI training, as companies seek large volumes of printed books that predate the generative AI boom. ISBNdb, which says it maintains the world's largest book database, now helps AI companies source physical books in bulk. The company says it can coordinate purchases ranging from 1,000 to 1 million books, drawing from secondary markets where libraries, retailers, and individuals sell used inventory.
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 represent curated, peer-reviewed, domain-specific human knowledge, structured in a way no web crawl can replicate. Dense, edited, authoritative."
The focus is largely on books published before 2022, before synthetic text became widespread online. That matters because AI models trained on AI-generated content can degrade over time, a problem often referred to as model collapse. ISBNdb frames print as a way around that risk. "Print books from the pre-LLM era are structurally guaranteed to be free of this contamination," the company says. "Physical books published before this date [pre-2022] are structurally clean of modern poisoning tools."
To make that usable at scale, ISBNdb combines its catalog with sourcing services that help buyers avoid duplicate titles and assemble large, varied datasets. It also emphasizes confidentiality. The site says every engagement is covered by a strict nondisclosure agreement and that the buyer's identity, strategy, and acquisition targets are kept confidential.
– Charlie D. Becker (@charliedbecker) July 28, 2026
That lack of transparency carries over into the marketplaces supplying the books. Sellers on platforms like Alibris and Biblio say they have seen a sharp increase in bulk orders in recent months, though the buyers are not identified.
One bookseller who specializes in foreign-language titles said sales changed dramatically starting in April. "I personally have mixed feelings about all of this," the seller told 404 Media. "It benefits me financially as well as by clearing out old inventory that is otherwise unlikely to sell. I've been well-suited for these sales with inventory from overseas and foreign language books. On the other hand, I don't like the end-use, and I don't like that uncommon books are being pulped."
The orders themselves stand out. Instead of focusing on a subject area, they appear scattered across topics and formats. The seller said the orders were unusual not just because of their size, but because they seemed random and ignored normal pricing patterns. The seller also suggested that the pattern looked like AI-related purchasing because of the scale of spending.
Other sellers are seeing similar patterns. On an Alibris forum, one user asked, "Is it just me, or has there been an uptick in the number of AutoBuy orders since the tail end of last year?" Mike Feldman, director of client services at Alibris, replied, "We have a couple of new bulk buyers that are scooping up trade books so lots of sellers are getting lots of orders."
There is no direct confirmation that these purchases are tied to specific AI companies, but recent court cases show how printed books are being used. In a lawsuit involving Anthropic, internal documents described a plan to buy and scan millions of books. In many cases, the books were destroyed during the process.
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