Berkley Books, a Penguin imprint for commercial and genre fiction, will join forces with Penguin Young Readers to launch Berkley XO, billed as an adult-YA crossover imprint. Announced today by Penguin Young Readers president Jennifer Loja and Berkley publisher Christine Ball, Berkley XO will publish a “highly curated” list of no more than 10 fiction titles per year, pulling talent from both parent imprints to assemble custom teams for each book. Ball and Loja will oversee the imprint’s publishing strategy, with Jen Klonsky, publisher at Penguin’s Putnam Books for Young Readers, and Berkley editor-in-chief Claire Zion leading a team of editors from both divisions in acquiring titles for the Berkley XO list.

In a conversation with PW, Ball spoke to the limitations of marketing certain novels, especially genre titles, as strictly “adult” or “YA.” “Within genre publishing, there is more of an overlap in adult and young adult readers,” Ball said. “And the readers of Penguin Young Readers are our potential future Berkley readers.” Ball noted that Penguin Young Readers and Berkley have already been collaborating on titles for some time; Berkley XO will make the teamwork official. While most likely not every Berkley XO title will be suitable for schools and libraries, Ball said, the large majority of the books will be “equally at home on a YA shelf, or on an adult fiction shelf.”

The significant adult audience for YA titles has been common knowledge for more than a decade, and the drive to appeal to those readers has, according to some, pushed the YA genre to become edgier and more sophisticated. Berkley XO joins a small group of imprints—like Macmillan’s Wednesday Books, which launched in 2016—that embrace the fluidity between the YA and adult categories. Loja said that Berkley XO “doesn’t just aim to reach a crossover audience,” but also puts its titles’ hybrid appeal to the front of editorial and production decisions.

The launch of Berkley XO also comes amid a growing investment in the new adult category, which bridges YA and adult with its focus on characters in early adulthood—older than the typical YA lead, but younger than most protagonists in adult fiction. While the category isn’t new, publishers have taken keener interest in it over the past few years, with Entangled Publishing, Little, Brown Books for Young Readers, and the aforementioned Wednesday Books all launching new adult imprints of their own.

“As the lines between adult and young adult fiction continue to blur, Berkley XO will embrace the opportunity to publish a select list of titles aimed at readers of both,” said Ball. “This new hand-in-hand approach will serve our authors by reaching a wider range of readers who straddle the divide between adult and YA.”