A judge in New Jersey dismissed on Wednesday a $5 billion defamation lawsuit filed by Donald J. Trump against an author whose book placed Mr. Trump’s personal wealth far below his public estimates.

Superior Court Judge Michele M. Fox in Camden, N.J., found there was insufficient evidence to allow the case to go to trial.

Mr. Trump sued the author, Timothy L. O’Brien, in 2006 after his book “Trump Nation: The Art of Being the Donald” placed Mr. Trump’s wealth at $150 million to $250 million, citing three confidential sources. Mr. Trump argued it was in the billions.

Mr. Trump failed to demonstrate “clear and convincing evidence to establish malice,” Judge Fox ruled, according to Bloomberg News.