President Donald Trump's niece Mary L. Trump is publishing a book that will reveal herself to be the primary source of a New York Times investigation into the president's finances, The Daily Beast reported. Mary Trump will say she supplied The Times with confidential family tax documents, The Daily Beast said. The Times investigation later revealed that the president wasn't a self-made man but had his father bolster his failing businesses in the 1990s with hundreds of millions of dollars. Mary Trump is the daughter of Fred Trump Jr., the president's older brother who died in 1981 at the age...