Jason Rekulak has resigned as publisher of Quirk Books. Brett Cohen, the president of Quirk, has taken over as publisher, effective immediately.

Quirk said in a statement that Rekulak is stepping down in order to "further pursue his writing career and other creative projects." Cohen said: “As a colleague and a friend, it is with mixed feelings and a heavy heart that I accepted Jason’s resignation.” He went on to say that Rekulak's "relentless pursuit of unique and innovative projects across a wide spectrum of categories has laid a creative blueprint that will allow Quirk to continue to deliver on our mission for years to come. Of all his immense contributions to Quirk, I am most thankful for his leadership and mentorship.”

Rekulak, who has been with the Philadelphia-based publisher for 18 years, was instrumental in the publication of such bestsellers as Seth Grahame-Smith's Pride and Prejudice and Zombies and Ransom Riggs’s Miss Peregrine’s Peculiar Children series, which he edited. In his increased role, Cohen will continue to oversee Quirk’s operations while also having creative oversight of all goings-on at the publisher—a move that unifies all management of the publisher under Cohen.

“With 17 years at Quirk Books, Brett is a seasoned publishing professional who has a deep understanding of our business as well as of our publishing and entertainment vision,” David Borgenicht, owner and CEO of parent company Quirk Productions, said in a statement. “Brett knows Quirk inside and out, and he knows how to balance art and commerce to achieve huge commercial (and cultural) impact and success.”

Although Rekulak’s resignation is effective immediately, Quirk will, the publisher said, begin a transition period that will extend through March, and will, the publisher added, "explore a new relationship with Rekulak beyond that point." Quirk will undertake a search for an editorial director, who will be responsible for acquiring new projects and managing overall development of the list, in the coming weeks.