WWW- [NY Daily News]- O.J. Simpson’s kill-and-tell book sickened America, but it was the crass sullying of New York hero Mickey Mantle that finally toppled publisher Judith Regan, according to New York magazine.

In a behind-the-scenes look at the scandal that rocked Rupert Murdoch’s News Corp., the magazine claims the outcry against O.J.’s book, “If I Did It,” left the famously temperamental Regan reeling, but still working.

It was her next project, a fictional account of Mantle’s past filled with pornography, foul jokes and a seamy affair with Marilyn Monroe, which led to her downfall after the Daily News splashed it on page one.

“The supposed sullying of Mantle’s name hit the cover of the Daily News,” says the New York magazine piece, published tomorrow. And “[Harper Collins’ CEO Jane] Friedman hit the roof.”

“By this point, Friedman was sick of playing nice,” the mag continued. “News Corp. executives were appalled, as was [News Corp. mogul] Murdoch.”

“Mickey Mantle felt like another major blunder,” says one executive of the book, which was to be called, “7: The Mickey Mantle Novel.” “It just reinforced the sense that [Regan was] an irresponsible editor.”

The falling ax hit Regan, who headed ReganBooks – an arm of Harper Collins. And it fell on the day News Corp. employees, including the staff of the money-losing New York Post, were celebrating their holiday party in New York’s Hilton Hotel.

The firing was ordered directly by Murdoch, although its seasonal timing surprised even him, the magazine reports.

But the last to know was Regan herself.

“Everyone was shepherded into the conference room, where a long-suffering ReganBooks deputy made the announcement: Judith has been fired,” the mag recounts.

Workers were told Regan had already been escorted from the building, but they later found her eating a sandwich at her desk, ignorant of her firing.

“So I’m eating a sandwich,” the magazine reports her telling workers. “Why are you staring at me?”

Regan, who is now reported to be planning a break from work to travel, had apparently seen the O.J. book as the pinnacle of her career, the magazine article says.

But Simpson’s hypothetical discussion of how he would have killed Nicole Brown Simpson and her friend Ronald Goldman disgusted the nation – and outraged relatives of the victims.

Regan was encouraged to speak out in favor of the book – including giving interviews about personal experience of domestic abuse – by News Corp. executives eager to make her take the heat, the magazine says.

“Executives had begun to realize they needed a villain, a scapegoat, distancing the company from the project, making it one woman’s mad dream,” the article reports.

The O.J. book was eventually canned and so was the Mickey Mantle project.

The magazine said talk of Regan’s firing at the holiday party was met with applause by many News Corp. staffers.

“Friedman told editors that she had fired Regan,” says the article. “When she said it, people began to clap.”