A former New York Times reporter's biography, written a decade before Trump entered politics, that set out to establish his actual net worth against his own public claims — and concluded the real figure was a small fraction of what Trump asserted.
Trump sued O'Brien and his publisher for defamation over the book's net-worth estimate; the suit was eventually dismissed, but the underlying dispute — self-reported wealth versus documented reality — became a template that recurs in nearly every subsequent account of Trump's finances.
O'Brien's reporting draws on confidential sources close to Trump and internal financial documents, and situates the wealth question inside a broader psychological portrait: a subject for whom the appearance of wealth was, at times, more important to defend than the wealth itself.
As the earliest serious attempt to fact-check the fortune at the center of this tracker's subject, it's the origin point for a genre of Trump financial reporting that continues today.