George Bush and his son George W. Bush did not vote for fellow Republican Donald Trump last year, says the author of a new book on the 41st and 43rd U.S. presidents in which they open up about their disapproval of the man now occupying the White House.

The elder Bush voted for Hillary Clinton, while his son voted for neither Trump nor his Democratic challenger, or "none of the above," said Mark K. Updegrove, who wrote "The Last Republicans" with the cooperation of the two Bushes. HarperCollins will publish the book on Nov. 14.

In an interview with The New York Times, Updegrove said the elder Bush, 93, who served as president from 1989 to 1993, had an instinctive dislike of Trump though he did not know him personally.