Generative AI can now be used to write entire books. But is that a good idea?
A new research paper co-written by a Digital Fellow at the MIT Initiative on the Digital Economy finds reason for concern. The researchers found that books written with AI assistance are both flooding the market and diluting sales.
To get their findings, the research team—which includes Paramveer Dhillon, a Research Affiliate at the IDE and assistant professor at the University of Michigan’s School of Information—examined over 14,400 self-published genre fiction books sold on Amazon over a three-year period.
They then used an AI-detection tool to determine which of the books had been written with AI assistance, and to what degree AI had been used. Finally, the researchers analyzed the impact these self-published books had on the overall market.
What’s at Stake?
Self-published books, once a publishing backwater, have become a major industry force. In 2025 more than 3.5 million self-published books (mainly e-books) were released in the United States, up from 2.5 million the year before, . Those self-published books represented about 85% of all titles published that year.
Most self-published books are offered on Amazon’s Kindle Direct Publishing. This platform attracts authors mainly because it’s an essentially free service that requires no gatekeeping.
Some of these books are written entirely with AI. For example, The New York Times recently interviewed a man, Bill Johns, who has placed 445 books for sale on Amazon, all of them written entirely by ChatGPT. Although some of Johns’ titles have yet to sell a single copy, he tries to generate 10 new books a week, the maximum Amazon allows.
Another person, Coral Hart, used AI chatbots to write and publish 200 romance novels under 21 pen names in just one year. Collectively, Hart’s books have reportedly sold some 50,000 copies.
Some books with substantial AI text earn considerable revenue. The researchers found one such book that sold over 80,000 copies in a single year, generating sales of $643,000. They also identified eight books with AI text, all associated with a single top author, that collectively earned one-year sales of $1.7 million.
Unfortunately, many AI-generated books are so poorly written, they’ve earned the designation of “slop.” And typically, neither Amazon nor the authors indicate that the books have been written with or by AI. That led one reviewer of a book published under Johns’ name to write: “Shame on Amazon for allowing people to sell AI slop without at least informing its customers.”
How the Research Was Conducted
Given this fast-changing field, the researchers sought to explore the dynamics of AI-generated books. As the researchers explain in their paper, Generative AI Floods and Dilutes the Market for Books, they began by asking four questions:
- Do books with substantial AI text occupy only the bottom of the market? Or are they competitive enough to sell and rank alongside books with no AI content?
- Do books with AI content expand the market or dilute it? That is, do they take sales and rank away from books with no AI content?
- Do AI-using producers release books at rates far beyond what’s possible with human-only writing?
- Among successful books in terms of revenue, do those with substantial AI content draw on the more distinctive language of existing books than do those with no AI content? That is, are they “scraping” and copying text from other books, possibly in violation of copyright law?
To provide answers, the researchers examined a total of 14,419 self-published genre books sold on Amazon from 2023 to mid-2026. The researchers acquired all the books legally, asking authors for copies, borrowing e-books from libraries, and purchasing the others from Amazon.
Next, the researchers clustered the books into eight genre categories. These included general romance, fantasy/supernatural/horror, and mystery/thriller/crime.
The researchers then set out to discover the degree to which these books were written with AI. For this task, they used Pangram, a popular AI-detection tool.
Based on the results of Pangram’s scan, each book was then assigned to one of three categories:
- Books with no AI text
- Books with light AI text, representing 25% or less of the total manuscript
- Books with substantial AI text, representing more than 25% of the total manuscript
How AI-Assisted Writing Is Changing Publishing
Armed with this information, the researchers found that books written with AI have had an overall negative effect on publishing, both flooding the market and diluting sales. That’s because books containing substantial AI text are largely responsible for the increase in books published, even though most of these books sell very few copies.
More specifically, from January 2023 to March 2026, while the cumulative catalog of books released grew 38-fold, quarterly sales grew only 7-fold, the researchers report. Revenue per book fell across most genres, too.
In addition, while books with substantial AI text made up 20% of all books in the sample, they represented only 12% of unit sales and about 11% of revenue.
AI-generated books also create competition for the top ranks formerly held by books with no AI text, the researchers found. Books with no AI text lose the most ground in genres with high AI diffusion, and most of all in genres where Kindle Unlimited availability is high.
How about re-using text from other books? Here, the researchers found that indeed, many AI-written books draw on distinctive language from existing books.
The degree of copying is high. The researchers found that among the top 50 selling books, those with substantial AI text derived nearly half their text (45%) with rare expressions occurring in existing books. Examples include “The question circled his mind like a vulture” and “my stomach flip-flopping like a fish out of water.”
As the researchers point out, this finding has major implications for debates—and lawsuits—over the border separating fair use from copyright infringement.
The main takeaway? As the researchers write, “generative AI reshaped the book market without competing on quality at all, displacing revenue and top ranks through sheer volume of books alone.”
Discover More
- Read the full research paper: Generative AI Floods and Dilutes the Market for Books, by Tuhin Chakrabarty, Xinyue Liu, Jane C. Ginsburg and Paramveer Dhillon
- Learn more about the MIT Initiative on the Digital Economy (IDE)
Peter Krass is a contributing writer and editor to the IDE.