Judith Regan, the former book publisher, charges in a new lawsuit that a senior executive at News Corporation told her to lie to federal prosecutors about her relationship with embattled former police commissioner Bernard Kerik in efforts to protect Rudy Giuliani’s presidential aspirations.

The detail-laden, 70-page suit, filed by Ms. Regan, 54, yesterday in New York State Supreme Court in Manhattan, seeks $100 million, and charges that her former employers, HarperCollins Publishing and the publisher’s parent company, News Corporation, orchestrated a “smear campaign” against her, and that she was wrongfully fired in December 2006.

Ms. Regan charges that the smear campaign began in 2001, when she met Mr. Kerik, who was writing a memoir, “The Lost Son,” about his difficult childhood, and the two began having an affair.

According to the suit, an unnamed executive told Ms. Regan in December 2004 that he believed she had information about Mr. Kerik that would harm his nomination to the Department of Homeland Security, and Mr. Giuliani’s planned presidential campaign. Several executives then told Ms. Regan to withhold the information from investigators, Ms. Regan charges, a request she believes was designed to “advance News Corporation’s political agenda,” including efforts by executives to “sacrifice Regan in order to save the reputation of Kerik, and by association, Rudy Giuliani,” according to the complaint.

Mr. Giuliani recommended Mr. Kerik to be secretary of Homeland Security, but Mr. Kerik withdrew because of mounting allegations that he did not report wages he paid to a nanny. The suit says it is “widely accepted that one of Giuliani’s major political vulnerabilities is his association with Bernard Kerik.”

The complaint further explains in detail the situation surrounding Ms. Regan’s unceremonious firing last December, when, the suit says, she received a two-sentence fax late on a Friday night after the news of her dismissal had already been leaked to the New York Times.

Executives have said Ms. Regan was fired for anti-Semitic comments when she allegedly complained to a HarperCollins attorney that there was a “Jewish cabal” against her in the book industry. In bold and in underline type, the suit says those charges were “completely fabricated.”

It was the “accumulation of her behavior” that caused her firing, according to a News Corporation executive quoted in the suit, who points to the controversial O.J. Simpson memoir, “If I Did It,” which provided a hypothetical confession of the murders of Nicole Brown Simpson and Ronald Goldman, a “salacious” biography of Mickey Mantle, and Ms. Regan’s anti-Semitic allegations. The suit also charges that HarperCollins and News Corporation executives regularly worked to “undermine” Ms. Regan and ruin her credibility, including a period in which they allegedly planted employees within her own imprint, ReganBooks, to spy on Ms. Regan, and then encouraged the employees to file complaints about her behavior to the human resources department.

News Corporation applies a “double standard and [engages in] discrimination” against women, Ms. Regan charges, pointing to the fact that she was fired and smeared and that no action was taken in response to earlier complaints about the rampant sexist atmosphere. Repeated calls and e-mail messages sent to spokesmen at HarperCollins and News Corporation were not returned yesterday evening.

Howard Rubenstein, a spokesman for News Corporation, told the Associated Press that “the claims are preposterous.”

Ms. Regan was fired last December, although her contract was set to expire in June 2009. She had been with HarperCollins for more than 12 years, and in 1994 set up ReganBooks, which published five books that were No. 1 on the New York Times bestseller list. Her books generated more than $1 billion in sales for HarperCollins, the suit says.

In the December issue of Harper’s Bazaar, which will be on newsstands next week, Ms. Regan reflects in a first-person account the details surrounding her firing at HarperCollins and consequent ordeal as she faced scrutiny and “mayhem.”

“My one regret is that I spent too much time in the office. I gave so much to my work, and honestly, it wasn’t worth it,” Ms. Regan says in the article.