Black Dog Leventhal founder and publisher J.P. Leventhal will step down on December 31 after 25 years with the company. BDL, which Hachette Book Group bought in January 2015, has been folded into HBG’s Running Press imprint, effective immediately.

“I am so proud of the many wonderful books we have published over the past twenty-five years, and of the smart, dynamic and dedicated team that built us to be the creative, market-responsive house that we are today,” Leventhal said in a statement. “What fun we’ve had.”

The Black Dog Leventhal team will report to Kristin Kiser, v-p and publisher of Running Press. The publisher, best known for its nonfiction and illustrated books including The Complete Cartoons of The New Yorker, The New York Times: The Complete Front Pages, and The Louvre: All the Paintings, will publish The New Yorker Encyclopedia of Cartoons next year.

“J.P. Leventhal has been a force in publishing, an original, and a splendid collaborator,” HBG CEO Michael Pietsch said in a statement. “His genius for bringing visual content into books in new ways has brought joy to millions of readers. It has been a pleasure having him and his team become part of HBG, and we look forward to his DNA living on in the imprint he created.”