NEW YORK (AP) — Macmillan's longtime CEO, John Sargent, will be leaving at the end of the year, forced out by what parent company Holtzbrinck Publishing Group is calling “a disagreement regarding the direction of Macmillan.”

Macmillan spokesperson Erin Coffey told The Associated Press on Thursday that Sargent's departure was the decision of Stefan von Holtzbrinck, CEO of the Holtzbrinck group, which declined to specify the disagreement. Sargent, who joined Macmillan in 1996, declined comment.

“The family shareholders, the supervisory board, my colleagues and I thank John Sargent deeply for making Macmillan a strong and highly successful publishing house and for his most helpful advice," von Holtzbrinck said in a statement. “John’s principles and exemplary leadership have always been grounded in worthy, essential causes, be it freedom of speech, the environment, or support for the most vulnerable. Since Holtzbrinck shares these ideals, they will live on.”

Sargent will be replaced by Don Weisberg, currently Macmillan's president. Macmillan, one of the so-called Big Five in the book business, publishes authors ranging from “Wolf Hall" novelist Hilary Mantel to former FBI Director James Comey.

The 63-year-old Sargent is widely known for his direct and straightforward style, the kind of executive who rarely wore a suit, often answered his own phone and would stick to a decision once he made it. A decade ago, he was at the heart of an industry battle with Amazon.com, when the online giant removed the “buy” buttons" from Macmillan books because of a dispute over e-book prices. The weeklong standoff led to Amazon's agreeing to Macmillan rating prices for e-books, sales for which had been quickly rising. Two years later, Macmillan and four other publishers were sued by the Justice Department for alleged price fixing. Macmillan was among those settling out of court.

In 2017, PEN American honored Sargent for “his fierce advocacy for the right to publish and for serving as a defender of publishers’ and authors’ intellectual property rights.” A year later, Sargent insisted on publishing Comey's memoir, “A Higher Loyalty,” even as he faced legal threats from the administration of President Donald Trump.

Over the summer, as Macmillan and other publishers faced criticism for lack of diversity, Sargent announced that he was stepping back from daily operations, saying “It is clear that we have to change who occupies the seats at the table when the important decisions are being made.” But Macmillan employees expressed surprise and dismay over Thursday's news, saying they had not sensed any tension between Sargent and Holtzbrinck.

Sargent will prepare to go at a time when Macmillan has rebounded from losses sustained during the early part of the pandemic; salaries were cut in the spring, but have been restored. In a weekly company memo dated Sept. 11 and shared with The Associated Press, Sargent acknowledged the challenges of publishing during the coronavirus pandemic, but said he was “full of optimism” about the fall.

"In closing this week, I note that it is 9/11 and it has been a half year since we left the office due to the pandemic," he wrote. “As the seasons, the years, and the decades scroll by, I marvel at our ability collectively, and your ability singularly, to handle adversity in all its forms. Bring on the Autumn!”