When Mark Siegel founded First Second Books in 2006—long before the Macmillan imprint became the toast of the town thanks to blockbuster books by Gene Luen Yang and the Tamaki cousins, and a list that includes books by Faith Erin Hicks, Scott MccLoud, Rainbow Rowell, Tillie Walden, and even the legendary animator Hayao Miyazaki—he knew it was built to last.

“That's why I didn't want to call it Mark Siegel Books or something,” he told PW. “It's not about one person. The best test of a thing is if it can outlive all of us and still be true.”

Nearly two decades later, First Second has lasted so successfully that it has found itself with a sister imprint, 23rd Street Books, which will launch next fall with a focus on graphic novels for adults. 23rd Street aims to publish 10–12 books a year to start, in addition to First Second’s current list of 45–50 annual titles.

The imprint will also become home to First Second’s backlist collection of adult graphic novels, as well as future titles in such marquee series as The Adventure Zone. Both Yang and Zita the Spacegirl creator Ben Hatke, long fixtures of the First Second list, have projects with 23rd Street in 2025, as do actor and comedian Damon Wayans Jr., poet and performer Saul Williams, and others.

Siegel will lead both First Second and 23rd Street as VP and executive editorial and creative director, along with with editorial director Calista Brill, who joined first Second in 2008, working with Siegel on both imprints as well, and creative director Kirk Benshoff. All three report to Allison Verost, SVP and publisher of Roaring Brook Press, Farrar Straus & Giroux Books for Young Readers, and First Second Books.

“Far more than a publishing catalog, this new imprint is a creative lab, an incubator for the future of the medium,” Verost said in a statement. “Beyond capitalizing on an existing market, 23rd Street aims to lead it, shape it, and champion its most visionary minds.”

Including Siegel, Brill, and Benshoff, both imprints employ roughly a dozen people in editorial and design combined, in addition to sharing staffers with Macmillan proper in such departments as publicity and marketing. Recent hires include editor Tess Banta, with more hires to be announced in the coming year.

The move, Siegel said, is less a strategic repositioning of First Second in the marketplace as it is “a flowering of First Second. It's a sign of success,” he explained. “First Second is adding more specialized attention and expertise and support to its adult program, and distinguishing it—it will become very much its own entity, but they're still two sides of the same coin.”

Siegel pointed to the imprint’s name as a case in point. “Sometimes, we contrive stuff, and we think we're being very clever, but I tend to trust the stuff that comes up neat,” he explained. Like First Second, 23rd Street just “turned up,” Siegel said: the street of the same name, in Manhattan, happened to be both the northern boundary of Macmillan’s former office space, in the Flatiron building, and—shockingly, to Siegel—a freely available web domain.

"As soon as I put it down on a piece of paper and I saw ‘01’ next to it, I thought, ‘Oh, right! It’s First Second growing,’” Siegel said. “It’s ‘01,’ and now plus ‘23.’ It's an organic evolution.”

As part of that evolution, First Second will shift its stylistically eclectic, creator-driven program into exclusively publishing graphic novels aimed at children and teenagers. That move too, Siegel explained, was natural.

“First Second’s reputation has really grown its strongest around young readers and YA,” he said. And in pulling the adult backlist from First Second to 23rd Street, “the magic here,” Siegel added, “is that we're not starting from scratch.”