The author of a book about the funding of terrorism has asked a federal judge to protect her against court judgments obtained by a Saudi billionaire who has successfully sued other authors in British courts.

Rachel Ehrenfeld, the author of “Funding Evil: How Terrorism is Financed – and How to Stop It,” published last year, filed a lawsuit Wednesday in U.S. District Court in Manhattan against the Saudi businessman Khalid Salim A. bin Mahfouz.

In the lawsuit, made publicly available yesterday, Ms. Ehrenfeld asked the court to declare that Mr. bin Mahfouz could not win a claim of libel against her under U.S. law and thus any award is not enforceable in America.

According to the court papers, Ms. Ehrenfeld seeks relief from American courts because she was not properly served notice and lacks the finances to fight a defamation lawsuit Mr. bin Mahfouz brought in London against Ms. Ehrenfeld for her published comments about him.

Ms. Ehrenfeld, of Manhattan, said in her court papers that her book cited Mr. bin Mahfouz after her research revealed substantial credible evidence of his role as a financial supporter of terrorist organizations.

A Web site for the bin Mahfouz family contains a statement which says a number of “serious errors of fact” about the family have been published. According to the statement, the family “abhors violence as a way of achieving political or other objectives.”

An e-mail message to the Web site seeking comment from the family was not immediately returned.