In August 2016, Colleen Hoover’s It Ends with Us was published by Simon & Schuster’s Atria Books. By the end of its first month on the market, the novel had sold about 21,000 copies at outlets that report to NPD BookScan. The publicity was good—a nine-stop national book tour, blurbs from bestselling authors—and the book hit bestseller lists in its first week on sale, but sales flatlined after that initial month. For several years, weekly sales rarely broke triple digits. Then something changed.

Libby McGuire, senior v-p and publisher of Atria, first noticed a sales bump in November 2020. By the summer of 2021, the bump became a surge: since the start of June, weekly sales have averaged about 17,000. McGuire said Atria has gone back to press 24 times since November to keep up with demand. “We are printing as quickly as we can,” she said, “and expect to go back several times through the fall.” The novel has sold more than 308,000 copies since the start of 2021—with sales peaking at just over 29,000 copies in the week ended August 14—and just shy of 450,000 since its 2016 release, according to BookScan.

It Ends with Us has become what Atria’s senior associate director of publicity, Ariele Fredman, called “the book of the summer”—despite the fact that it was published five summers ago. “Sometimes the book of the summer is not always the newest book,” Fredman said, noting that that jump in It Ends with Us sales is a good example of why publishers should maintain their backlist, “because [a book] can pop at any time.”

The rise in interest in It Ends with Us is one of the best examples of the impact of TikTok on book sales. A large community of TikTok users have carved out a corner of the app—called “BookTok” and codified through hashtags—for sharing their favorite books and authors. TikTok’s vibrant literary subculture emerged around the onset of the pandemic, when more young people were confined to their bedrooms, with few options for entertainment other than reading. BookTok influencers are predominantly teenagers and young women, excited to share their book-related opinions, rankings, and recommendations. When a book catches on among users (a common hashtag on BookTok videos is #TikTokMade­Me­ReadIt), the real-world results can be impressive.

BookTok content reaches an extremely large audience—videos with the #BookTok hashtag have racked up a combined 18 billion views. Once a book like It Ends with Us is recommended by influencers, TikTok’s algorithm ensures that it pops up on users’ feeds without them even searching for it. As of this writing, videos with the hashtag #ItEndsWithUs have a combined 73 million views.

BookTok’s power to promote books relies on its grassroots nature. Through self-made content, users create the sort of literary publicity that, in its sincerity, money literally cannot buy. Media-literate young people are especially drawn to promotion done by peers with no financial stake in a product. But publishers have taken notice and are responding swiftly. Atria’s chief marketing officer, Liz Perl, said it’s important to take TikTok seriously as a promotional tool because it’s “not just for kids anymore.” Perl said the publisher has been working closely with authors to “capitalize on this moment by creating more organic content, investing in more paid campaigns and working with a broad variety of book influencers.”

“From a marketing and publicity perspective, we jumped on the TikTok trend as soon as possible,” said Fredman. To leverage the app’s influence, the marketing department has created an @AtriaBooks account and is building relationships with BookTok influencers. Publicists want to get books into influencers’ hands, but they are also strategic, ensuring that they are tailoring outreach to their tastes and interests. “It’s not just about sharing books,” Fredman said. “It’s about sharing the right books to cultivate relationships.”

In many ways, booksellers have responded even more quickly to BookTok than publishers. “BookTok has been a huge sales driver for us since summer of last year,” said Shannon DeVito, director of category management at Barnes & Noble. B&N’s shift to give local managers more authority in ordering came at a good time for BookTok, DeVito said, since local booksellers can point out key titles in their areas. She has seen B&N booksellers across the country “fully taking advantage of this absolutely massive trend by setting their own unique displays,” including tables and endcaps that showcase BookTok-backed titles.

And it’s not just in-store merchandising that has been affected. B&N’s website has an entire category devoted to BookTok, which not only lists the app’s most popular titles but also includes a brief explanation of BookTok itself. Books-A-Million and Canada’s Indigo Books & Music have also installed BookTok categories on their websites for online shoppers to browse.

While literary communities like BookTube and Bookstagram have already sprung up on social media, DeVito said BookTok has been a “game changer.” Unique to TikTok is “the staying power of these titles once they start trending on the app,” she said. “Our booksellers are able to buy deeper—and I like to think intelligently so—because the top titles and recommendations maintain high volume for weeks and months on end.” The bump in sales that follows a book’s popularity on YouTube and Instagram, on the other hand, is usually just a “flash in the pan,” she said.

BookTok’s impact on sales, and particularly trade paperback sales, has been “immense” at B&N, DeVito said. It Ends with Us has been a top 10 performer for B&N over the past four months, and its popularity has spurred interest in several of Hoover’s other backlist titles. DeVito also credits Hoover as “a core author” driving a recent uptick of interest in romance books. Across the country, B&N stores have spotlighted It Ends with Us on #BookTok displays, romance displays, and even entire displays dedicated to Hoover.

It Ends with Us is just one case study on the impact of BookTok on consumer tastes. Numerous other books have enjoyed similar surges in interest, including another Atria backlist title, The Seven Husbands of Evelyn Hugo by Taylor Jenkins Reid. Fredman has adjusted her publicity efforts accordingly, keeping both Hoover’s and Reid’s titles “top of mind when talking to media and pitching trend stories.”

Other books that have returned to bestseller lists after receiving significant BookTok buzz—notably all backlist, and mostly young adult fiction—include Adam Silvera’s They Both Die at the End (Quill Tree, 2017), Hanya Yanagihara’s A Little Life (Doubleday, 2015), E. Lockhart’s We Were Liars (Delacorte, 2014), and Madeline Miller’s The Song of Achilles (Ecco, 2011).

For a substantial portion of readers, all these books are also major tearjerkers. Whether a book can make its reader cry actually seems to be a prerequisite to earn BookTok’s approval—so much so, that a March 2021 New York Times article about BookTok was titled, “How Crying on TikTok Sells Books.” Many BookTokkers film time-lapse videos of themselves reading a popular book, with the aim of capturing the moment the book makes them cry.

In late March, BookTokker Eloise Hampson, whose handle is @kazzledazzlesteponme, captured in two parts her experience reading It Ends with Us. The first shows Hampson reading the last pages of the novel, taking intermittent breaks to sob. The second shows Hampson red-faced and bleary-eyed. “Update,” a voice-over reads, “its been 40 min and im still sobbing over the last line.” Combined, the two videos have nearly 2.4 million views.

Fredman suspects that the emotional intensity of It Ends with Us, which deals with such subjects as domestic violence and abusive relationships, has been essential to its virality on BookTok. By recommending the book to others, she said, readers are able to share profound feelings with one another. Fredman has seen many readers frame their recommendations in terms such as, “This book put me through the ringer, and I want to see if it does the same to you, and if... we can break it all down together.”

Despite all the concern in the industry that young people have supplanted books with screens, any sampling of BookTok videos suggests that is just not the case. The resurgence of It Ends with Us shows that young readers exist in droves and are hungry for titles that move them. It’s now up to publishers to get the right books into the right hands, booksellers to stock the right titles at the right time, and for everyone in the industry to get a bit more TikTok savvy.

This article has been updated with further information.