Another recent trend in the book industry involves the preservation of older books, especially those from the nineteenth century printed on acid-based paper, which gradually deteriorates. At the turn of the twentieth century, research initiated by libraries concerned with losing valuable older collections provided evidence that acid-based paper would eventually turn brittle and self-destruct. The paper industry, however, did not respond, so in the 1970s leading libraries began developing techniques to halt any further deterioration (although this process could not restore books to their original state). Finally, by the early 1990s, motivated almost entirely by economics rather than by the cultural value of books, the paper industry began producing acid-free paper. Libraries and book conservationists, however, still had to focus attention on older, at-risk books. Some institutions began photocopying original books onto acid-free paper and made the copies available to the public. Libraries then stored the originals, which were treated to halt further wear.

Another way to preserve books is through digital imaging. The most extensive digitization project, Google Books, which began in 2004, features partnerships with the New York Public Library and about twenty major university research libraries—including Harvard, Michigan, Oxford, and Stanford—to scan millions of books and make them available online. The Authors Guild and the Association of American Publishers initially sued Google for digitizing copyrighted books without permission. Google argued that displaying only a limited portion of the books was legal under “fair use” rules. Both sides forged an agreement in 2008 with Google, authors, and publishers sharing the revenue. But in 2011, a federal court struck down the agreement, arguing that it gave Google too much power to profit from millions of books for which Google didn’t first obtain copyright permission. An alternative group, dissatisfied by Google Books restricting its scanned book content from use by other commercial search services, started a nonprofit service in 2007. The Internet Archive’s Open Library works with the Boston Public Library, several university libraries, Amazon, Microsoft, and Yahoo! to digitize millions of books with expired copyrights and make them freely available at open library.org. In 2008, another group of universities formed the HathiTrust Digital Library to further archive and share digital collections. In 2010, these nonprofit archives joined other libraries to create the Digital Public Library of America.