Donald J. Trump, the real estate investor, said yesterday that he had filed a lawsuit against Timothy L. O'Brien, who wrote "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." Mr. O'Brien is also a reporter for The New York Times.

At issue is Mr. Trump's net worth, which Mr. O'Brien reported was $150 million to $250 million, citing three people with direct knowledge of Mr. Trump's finances. Mr. Trump contends that his net worth is at least $2.7 billion.

"TrumpNation" was published in October 2005 and excerpted in the Sunday Business section of The New York Times. A spokeswoman for The Times, Catherine J. Mathis, declined to comment on the lawsuit. The Times is not a party to the lawsuit, which seeks $5 billion.

In a statement, a spokesman for Warner Books, Rob Nissen, said: "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."