Donald J. Trump, the real estate investor made a statement yesterday saying that he had filed a lawsuit against Timothy L. O'Brien, the author of "TrumpNation: The Art of Being the Donald," and the book's publisher, Warner Books, for making what Mr. Trump called "egregiously false and malicious statements."

At issue is Mr. Trump's fortune, which The New York Times' reporter Timothy O'Brien reported to be 150 million to 250 million US dollars, citing three people with direct knowledge of Trump's finances and Trump's statement that his net worth is at least 2.7 billion US dollars.

"TrumpNation" was published in October 2005 and parts of it were also published in the Sunday Business section of The New York Times. A spokeswoman for The Times, Catherine J. Mathis, declined to comment on the lawsuit, which is seeking 5 billion US dollars in damages, as the newspaper is not a party to the lawsuit.

Rob Nissen, a spokesman for Warner Books, said that "Mr. O'Brien is an award-winning, veteran business reporter with The New York Times and his work, as does his book, 'TrumpNation,' speak for themselves. Mr. O'Brien has not seen nor has he been served with the court papers to which Mr. Trump is referring. But Mr. O'Brien welcomes the opportunity to meet with Mr. Trump personally at any time and in any forum to discuss the merits of 'TrumpNation,' a book in which Mr. Trump participated extensively and willingly."