Amy Einhorn, who recently left her eponymous imprint at Penguin Random House, is joining Macmillan’s Flatiron Books imprint as senior v-p and publisher. She will start at Flatiron on July 21.

Bob Miller, president and publisher of Flatiron, explained that the original plan was to publish only nonfiction books at the imprint. This notion has now changed.

“Forming this partnership offers us an irresistible way to expand,” Miller said. At Flatiron, Einhorn, “will continue to do what she does so well—find books that hit that sweet spot between literary and commercial—but with a larger canvas, hiring a staff of fiction editors who will acquire the best new voices.”

The addition of Einhorn, said Macmillan president John Sargent, makes Flatiron, “a full-spectrum new publishing company with tremendous potential.”

Miller, who will also continue to carry the publisher title, told PW that with Einhorn's arrival, editorial director Colin Dickerman, and his staff, will continue to report to him on their nonfiction acquisitions. Einhorn, meanwhile, will take the lead on fiction acquisitions.

No date has been set for the release of Einhorn's first titles, but Miller expects that she and her staff will ultimately publish about three books per month, which will double Flatiron's overall list.

Before creating her own imprint at Penguin, Einhorn worked at Farrar, Straus and Giroux, Poseidon Press, and Grand Central. Her list of books includes The Husband’s Secret by Liane Moriarty, The Help by Kathryn Stockett, and Let’s Pretend This Never Happened by Jenny Lawson

“Coming to work with Bob at Flatiron Books is a chance for one plus one to equal five,” said Einhorn. “It’s a tremendous opportunity to create the industry’s next great publishing house.”